# The &digikam; Handbook

## Introduction

### Background

#### About &digikam;

&digikam; is an advanced digital photo management application for the &kde; desktop. It provides a simple interface which makes importing and organizing digital photographs a "snap". &digikam; enables you to manage large numbers of digital photographs in Albums and to organize these photographs for easy retrieval using tags (keywords), captions, collections, dates, geolocation and searches. It has many features for viewing, organizing, processing and sharing your images. Thus, &digikam; is a formidable Digital Asset Management (DAM) software including powerful image editing functions.

An easy-to-use Camera interface is provided, that will connect to your digital camera and download photographs directly into &digikam; Albums. More than 1000 digital cameras are supported by the gphoto2 library. Of course, any media or card reader supported by your operating system will interface with &digikam;.

&digikam; incorporates a fast Image Editor with many image editing tools. You can use the Image Editor to view your photographs, comment and rate them, correct, enhance and alter them. The editing power can be easily extended by a set of plugins, the Kde Image Plugins Interface (manual)

While &digikam; remains easy to use, it provides professional level features by the dozens. It is fully 16 bit enabled including all available plugins, supports RAW format conversion through libraw, DNG export and ICC color management work flow.

#### New Features of the KDE4 version

- Runs on any platform that supports Qt4 and KDE4 (including Win32 and OS X)

- Supports XMP metadata

- Reads, writes and converts into DNG format

- New RAW processing tool, gamma-correction in 16 bits

- Preview of video and audio files

- Database file is independent of photo libraries, enabling remote paths, multiple roots and offline archives

- Improved database with many more metadata that can be searched, ⪚ camera or lens

- Marble integration, geographical filtering with the mouse on the map

- New search finds duplicates and similar images

- Help menu lists all RAW formats and &digikam; component versions

- DNG, RWL, NEF and PEF RAW file can be metadata edited

- Usability improvements for netbooks

- Non-modal image editor

- Thumbnail bar in preview mode

- Live search boxes in both sidebars and main window

- New camera interface, capture tool, scanner interface

- New plugin based on lensfun for automatic lens error corrections

#### Reporting Bugs

Like the rest of &kde;, &digikam; is an Open Source project. This means that it relies on its users to play their part by, at least, reporting problems and suggesting possible improvements.

&digikam; makes it as easy as possible for you to report bugs or suggest improvements. Wherever you are in the application the Help menu will include a Report Bugs option. This will display a message box with a highlighted link. Click on the link and your web browser will open the page for the reporting system. All the information required will already be filled in, just follow the instructions for completing your report.

#### Support

&digikam; is a community supported project, which means that users and developers support one another. If you become a regular user of &digikam; you are encouraged to join the &digikam; Users Mailing List. You can start off by asking questions of other &digikam; users and hopefully soon you will be answering the support questions of others.

&digikam; Users Mailing List joining instructions.

You can also visit the &digikam; Home Page. for news of new releases and other &digikam; related information.

#### Getting Involved

There are many ways that you can get involved with the continued development of &digikam;. You do not need to be a software developer. You can help with documentation, translation and user interface design or just contribute really good ideas to the wish-list. You can also get involved by testing early development code as it is being developed and providing feedback to the developers. Of course, if you are a software developer then you can help to make &digikam; the best digital photograph application there is.

The best way to start getting involved with &digikam; is to join the Developers Mailing List. &digikam; Developer Mailing List joining instructions.

### Getting Started

####

##### The First Run Dialog

When you start &digikam; for the very first time it will ask you where you store your photographs and the &digikam; database. You can choose any local, remote or removable folder. Just type in the path name of a folder or click on the folder icon Folder Icon to select a folder from the dialog.

Later on you can add as many locations as you like - &digikam; will add them to the album library. Settings Configure digiKam Collections

Choosing database path for digikam

Next, you will have to choose the way you would like to open RAW files : either with automatic adjustments or with the digiKam RAW import tool to adjust corrections manually.

If you don't know what is a RAW file or if your camera don't support RAW files, you should keep the default setting and skip this step.

RAW import

Metadata information storage may be important if you plan to work with another photo management program and you should Add information to files. But if you don't want to alter your pictures, keep the default setting: Do nothing.

Metadata information

Then choose how digiKam will load images in preview mode and light table. Reduced version will load faster but at the cost of quality.

Preview image method

Now how digiKam will open images on a right click. Previews will load faster but you won't be able to make any corrections.

Open image method

Tooltips are a fast and easy way to display important information on a photograph, they popup as the mouse move over a thumbnail. Select "Use tooltips" if you want to display them.

Tooltips

Click on Finish. DigiKam will now start to scan for photographs...

Tooltips

##### The Scan Items Dialog

If you already have a collection of photographs on your hard disk, you can enter the top-level folder containing the photographs, this is called the Albums Library folder. &digikam; will treat each sub-folder of the folder you've entered as an Album. None of the photographs will be altered. During folders parsing you can see a progress dialog like this:

&digikam; will recurse the library path to its full depth. You cannot exclude (prune) any sub-path unless you make that sub-path hidden. You have to do that from outside of &digikam; by putting a dot in front of the sub-path.

As &digikam; uses your folders on your hard disk directly, other applications like file managers can remove any albums outside a &digikam; session. In this case &digikam; will tell you at the next session if all albums that have been removed from the &digikam; photographs root path shall be deleted from albums database. If you want to move folders around and do not want to do that in &digikam;, we suggest you do that while &digikam; is running, so the database will be kept in sync and you do not lose any metadata.

When you use an existing folder of photographs, as the Album Library folder, you will notice that the Albums in the Album list do not have photographs as their icons. You can change that by dragging any photograph in the Album onto the folder icon in the left sidebar and use this as the Album icon. See the Album section for details of how to change the Album icon.

If you have previously accessed your photograph collection with another application, that has created thumbnails in non-standard sub-folders, &digikam; will show these thumbnail folders as separate Albums. &digikam; follows the freedesktop.org standards for thumbnail folders. There is no way of hiding non-standard thumbnail folders from the "Albums" list. If you want to keep them you could create an Album Collection that just contains all the thumbnail Folders and then view your Albums in By Collection order. See the Album section for more about Album Collections.

Once you have configured the Album Library Folder you can set up &digikam; to work with your digital camera. Then learn how to use Albums and Tags to arrange your photograph Albums.

&doc-file-formats;

### Supported Digital Still Cameras

RAW file support: if you are using RAW shooting mode with your camera, &digikam; is probably well able to deal with it. RAW support depends on the libraw library. To find out if your particular camera is supported, bring up the list of supported RAW cameras from the Help RAW camera support menu.

How to setup and work with RAW files is described in RAW Decoder Settings and RAW Workflow.

An easy-to-use camera interface is provided, that will connect to your digital camera and download photographs directly into &digikam; Albums. More than 1000 digital cameras are supported by the gphoto2 library. Of course, any media or card reader supported by your operating system will interface with &digikam;.

Current digital cameras are characterized by the use of Compact &Flash; Memory cards and USB or FireWire (IEEE-1394 or i-link) for data transmission. The actual transfers to a host computer are commonly carried out using the USB Mass Storage device class (so that the camera appears as a disk drive) or using the Picture Transfer Protocol (PTP) and its derivatives. Older cameras may use the Serial Port (RS-232) connection.

Preview Example | Connector Type
| FireWire (IEEE-1394 or i-link) connector from a professional digital still camera
| Universal Serial Bus (USB) connector from a consumer digital still camera
| Serial Port (RS-232) connector from an old digital still camera

Transfers using gPhoto2: PTP and RS-232 Serial Port

&digikam; employs the gPhoto2 program to communicate with digital still cameras. gPhoto2 is a free, redistributable set of digital camera software applications which supports a growing number of over 800 cameras. gPhoto2 has support for the Picture Transfer Protocol, which is a widely supported protocol developed by the International Imaging Industry Association to allow the transfer of images from digital cameras to computers and other peripheral devices without the need of additional device drivers.

Many old digital still cameras used Serial Port to communicate with host computer. Because photographs are big files and serial port transfers are slow, this connection is now obsolete. &digikam; supports these cameras and performs image transfers using the gPhoto2 program. You can find a complete list of supported digital cameras at this url.

libgphoto2 needs to be built with libexif to retrieve thumbnails to digiKam properly. EXIF support is required for thumbnail retrieval on some libgphoto2 camera drivers. If EXIF supported is not set with libgphoto2, you might not see thumbnails or the thumbnail extraction might be very slow.

Transfers using Mass Storage device

Of the devices that are not directly supported by gPhoto2, there is support for the Mass Storage protocol, which is well supported under &GNU;/&Linux;. This includes many digital cameras and Memory Card Readers. Mass Storage interfaces are:

- USB Mass Storage: a computer interface using communication protocols defined by the USB Implementers Forum that run on the Universal Serial Bus. This standard provides an interface to a variety of storage devices, including digital cameras.

- FireWire Mass Storage: a computer interface using communication protocols developed primarily by Apple Computer in the 1990s. FireWire offers high-speed communications and isochronous real-time data services. Like USB Mass Storage, this standard provides an interface to a variety of storage devices, including digital still cameras. Almost all recent digital cameras support USB version 1 and eventually will support USB version 2; a very few support FireWire.

To use a generic Mass Storage device with &digikam;, select Mounted Camera item in Camera Setup list and set the correct mount point path.

### Supported Plugins

One of the nicest things about &digikam; is how easily its functionality can be extended, by using plugins:

- Kipi Plugins: the Kde Image Plugins Interface project (Kipi) (manual) is an effort to develop a common plugin structure for &digikam;, KPhotoAlbum, Showimg and Gwenview. Its aim is to share image plugins among graphical applications. Kipi-Plugins setup is described in this section.

The &digikam; plugins interface

Plugins can manipulate images in almost any way that users can. Their advantage is, that it is much easier to add a capability to &digikam; by writing a small plugin than by modifying the &digikam; core.

## Using &digikam;

### The Main &digikam; Window

#### Introduction to the Main Window

&digikam;'s main window has four areas. The first one is a sidebar in the left margin that lets you switch between 4 views: Albums, Dates, Tags and Searches. Then there is a tree navigator panel showing the selected view. The main image window is right in the center. And on the right hand side there is another sidebar shown. This one can be used to show all information about your images. You can use all these views to organize and find your photographs.

To unclutter the interface, either toggle the sidebars away with a &LMB;, or use the full screen view mode (F11, Ctrl+Shift+F).

Drag and Drop of images works about everywhere: d&d an image into another branch of the album tree, across the horizontal album separation line, or to another application window. The only restriction is that you cannot d&d into tag, date or searches.

The status bar at the bottom shows in all four views:

- the file name when selecting a single file

- selection information when several items are selected

- progress bar for batch processes, ⪚ assigning tags

- Quick filters:

  - search string field: live filter on file names, captions (comments), and tags

  - a file type selector lets you single out the most common ones: JPEG, PNG, TIFF, RAW, movies and audio

  - a rating filter to select images rated with the clicked number of stars

- a thumbnail size slider

- a navigation bar that leads through the images in the main view

The text filter is only used for those fields which are actually displayed in the icon view. E.g. filename matching only works if filenames are displayed. The fields which are displayed can be configured in the album settings dialog.

The window top shows the menu bar and the main toolbar below.

The Default Main Toolbar

1. Go one view backwards in the main window view history (Alt+Left)

2. Go one view forwards in the main window view history (Alt+Right)

3. Add images, import function (Ctrl+I)

4. Create a new Album (Ctrl+N)

5. Edit Album properties

6. Quick Search tool (Ctrl+F)

7. View image (F3)

8. Open in Image Editor (F4)

9. Rename Image (F2)

10. Toggle Full Screen (Ctrl+Shift+F)

11. Slide Show (F9)

#### Albums View

The "Albums" tree provides an organized view of your photograph albums. All photographs that are managed by &digikam; are stored in a single folder branch. The albums can be sorted by their folder layout on the hard disk, by the Collection name that has been set in the Album Properties or by the Date of that Albums (this date can also be changed in the Properties of each Album).

You can switch between these sort orders using Sort Albums from the View menu.

##### Creating a New Album

There are a number of ways to create a new Album. You can create a new Album when you upload new photographs from the Camera using the Camera Tool. You can also create a new empty Album by clicking the New button on the tool bar. As an additional option, you can create a new Album by importing an existing folder of photographs from your computer; just select Import Add Folders... from the menu bar and select the folder that you want to import. An Album will be created with the same name as the hard disk folder. You can use drag and drop to import a folder. Drag a folder icon, for example from a &konqueror; window. Then drop it on the album list on the left. A menu will appear that gives you the option to move or copy the folder into &digikam;.

##### Deleting an Album

When you delete an Album from &digikam; it will be moved into the &kde; Trash Can. As an option you could change this behavior, so that delete really did remove the Album and all of the photographs in it. This can be changed by selecting Settings Configure &digikam; and selecting the Miscellaneous page. At the top of this page are the settings that control what happens when a photograph is deleted. To delete an Album right-click the Album in the "Albums" tree and select Delete Album from Hard Disk from the context menu.

##### Adding a Photograph to an Album

Most of the time you will create new Albums and populate them with photographs directly from your camera using the Camera Tool. However, sometimes you may want to add a photograph that you already have on your computer to an existing Album. To add a photograph to an Album, make sure that the Album is selected. Then, either click the Add Images icon in the tool bar or select Import Add Images... from the menu bar. Select the photographs that you want to add from the file dialog and click Open. The photographs will be copied into the Album. Additionally, you can use drag and drop to import photographs. Drag the photographs icons, for example from a &konqueror; window. Then drop it on the image list on the right hand side.

If you have a scanner configured, you can also scan a photograph straight into an Album. Select Import Import from Scanner....

##### Moving or Copying Photographs Between Albums

Simply drag the photograph and drop it on the destination Album to move or copy it from one Album to another. A menu will appear that gives you the option to Move or Copy the photograph. You can move or copy multiple photographs the same way, just select all the photographs that you want to move and drag them on to the destination Album.

##### Managing Albums

An Album contains a set of photographs. Album Properties allows you to set information about this set. To access the Album Properties right-click on an Album and select Edit Album Properties from the context menu.

The Album Properties dialog allows you to set:

###### The Album Properties Dialog

- The Album Title : this will be used in the "Albums" list.

- The Album Collection : this is a way of grouping your Albums together by a common label. The Collection you set will be used to order your albums when you select By Collection from the drop down box in the tool bar or using View Sort Albums By Collection. If you want to add and delete Collection labels, use the Collection Settings dialog.

- The Comments for the Album : this will be shown in the banner at the top of the main Image Window.

- The Album Date : this will be used when you order your Albums by date using View Sort Albums By Date.

- Oldest, Average, Newest buttons : these will set the Date to the oldest, average or latest date of the images in that album. It will first try to calculate the average date of the images in the album based on the EXIF-headers. If that fails it will fall back to the modification date of the files in that folder.

##### Setting the Album Icon

When you first view an Album, &digikam; selects the first photograph in the Album as the icon to display in the "Albums" list. This helps you remember what kind of photographs are contained in an Album. Sometimes the first photograph in the Album is not the most representative and you want to select a different one as the Album icon.

To select a different photograph as the Album icon, right-click on the photograph that you want to use as the Album icon and select "Set as Album Thumbnail" from the context menu. Additionally you can use drag and drop to set the Album icon. Drag the photographs icon and drop it on the currently selected Album in the Album list.

An Album can only be in one Album Collection and Album Collections cannot be nested.

&digikam; also supports tagging individual photographs using the "My Tags" area at the left of the main window. Album Collections are different from photograph tagging because the Album Collection applies to all the photographs in an Album rather than to individual photographs. You can use both Album Collections and tagging to organize your photographs.

#### Image View

##### Introduction

The Image Window provides the main view of your images. When you select an Album the images contained in that Album will be displayed in the Image Window. Each image is displayed as a thumbnail. You can alter the size of the thumbnails using the magnifier slider in the lower right of the status bar. The thumbnail size slider

The first time you select an Album you may have to wait briefly while the thumbnails are generated, unless you used the Tools Rebuild all Thumbnails... menu item beforehand.

Information about each photograph is displayed below each thumbnail. You can control what information is displayed from the Settings Configure &digikam; dialog. Select the Album View page and look for the Icon-View Options section.

The thumbnails have Tool Tips which will pop up if you allow the mouse to dwell over a thumbnail for a moment. The Tool Tip shows the most important properties of the photograph including any tags that you have applied. The screenshot at the top of the Introduction to the Main Window section shows a Tool Tip being displayed.

##### Image Management

Photographs are what &digikam; is all about. Albums and Tags allow you to organize and find your photographs in a way that suits you. You can access all of the functions that &digikam; can perform on a photograph by right-clicking the thumbnail (context menu) or by selecting from the Image menu in the menu bar. You have the choice between viewing the images, viewing by slide show, or of editing the images.

##### Viewing an image

There are several possibilities to view an image. You can either click on it, push F3 Image View... or &Enter; or select View from the context menu. The image will take the whole central space of the main window. For viewing it larger, click the sidebars away (by just clicking on them). While viewing images you can take action from the context menu at any time. To get back to the album view, just click again or press &Esc; or F3 puts you back into the main window. The viewer with thumbnail slider below

##### Editing a Photograph

You can open the Image Editor on a photograph either using F4 Image Edit... or by right-clicking and selecting Edit from the context menu. See the &digikam; Image Editor section for instructions on how to edit your photographs. The Image Editor lets you view your photographs and make a number of adjustments to them.

##### Viewing or Editing a Photograph With Another Application

Sometimes &digikam; may not provide all of the capabilities you need. You can open a photograph in another application by right-clicking on it and selecting from the Open With sub-menu. The list of applications that appear in this menu is controlled by the standard &kde; file associations for the image format type of this photograph. Consult the &kde; manual for instructions on changing these file associations if the application that you need is not listed.

Note that there can be a problem with meta-data embedded in photographs when they are edited by other image manipulation applications. Some applications do not retain the photograph's meta-data when you save a modified image. This means that if you modify a photograph using one of these programs you will lose information such as orientation, aperture &etc; that are stored in the EXIF and IPTC tags.

##### Lossless Image Rotation

You will need to have the Kipi JPEG Lossless Plugin installed for the rotation features. If you do not have this plugin installed you can still rotate your photographs, but you have use the Image Editor. The Image Editor uses a different method of rotating an image, you may not notice any difference but the Image Editor method can cause some loss of quality in the photograph when saving the picture as JPEG. The rotation methods described here uses the Kipi JPEG Lossless Plugin which preserve the quality in the original photograph.

&digikam; provides two ways to get your photographs the right way up. The simplest method is to right-click the thumbnail and select Rotate and then pick the correct amount of rotation needed.

Many digital cameras now have an orientation sensor. This sensor can detect how you hold the camera while taking an image. It stores this orientation information inside the image. This meta data is stored in an embedded meta-data section called EXIF. The cameras could rotate the image themselves right away, but they have limited processing power, so they leave this job to an application like &digikam;. If the camera is storing the orientation, then &digikam; can use it to automatically rotate your photographs so that they are the correct way up when you display them. &digikam; will rotate the image on disk according to this orientation information.

The photograph is rotated without loss of quality and the orientation information is set to normal, so that other EXIF-aware applications will handle it correctly. To use this feature, right-click on the thumbnail and select Image Auto Rotate/Flip Using EXIF Information . The Camera Tool can perform this operation automatically when it uploads the photographs from your camera which will ensure that your photographs are always the right way up. The rotate operation will do nothing if your camera does not include this information in the photos.

##### Renaming a Photograph

You can change the filename for a photograph by right-clicking a thumbnail and selecting F2 Rename . Remember to keep the file extension (.jpg, .tif, &etc;).

##### Deleting a Photograph

When you delete a photograph from &digikam; it will be moved to the &kde; Trash Can. F8 Image Delete or Delete If you prefer that Delete really removes the photograph completely, than you can do that by &Shift; Delete

Deleting works from anywhere in any &digikam; windows

#### Calendar View

Dates View from Main Window

The "Dates" view organizes your photographs based on their dates. &digikam; uses either the EXIF date or, if no EXIF date is available, the last modification time of the file.

When you select a month from the list, all images from that month are displayed in the Image View. You can select days or weeks in the date sheet at the bottom of the Date View to show only the images from the selected dates.

#### Tags View (Keywords)

(Hierarchical) tagging provides a flexible and powerful way to organize and catalog your images. Tags are labels that can be applied to individual images or whole groups. Once a tag has been set to an image it can be found again by selecting the tag or doing a search.

##### Selecting a tag and applying a new one

When a tag is selected, all of the images that are marked with that tag are displayed.

Tags can be arranged in a hierarchical tree. This allows you to organize your tags in a logical manner. One can collapse parts of the tree in the "Tags" list so that one can easily find the tags that you are looking for.

Tags are stored in a database for fast access, and, the applied tags are written into IPTC data fields of the image (at least for JPEG). So can use your tags with other programs or, in case of loss of that data in the database, the tags will be re-imported when the image is noticed by &digikam;.

##### Managing Tags

You can add new tags by right-clicking on either the "Tags" label or an existing tag and selecting New Tag. If you add a new tag by right-clicking on an existing tag, your new tag will be created as a sub-tag.

You can delete a Tag by right-clicking on the Tag you want to delete and selecting Delete Tag. When you delete a tag, the photographs themselves are not deleted. Simply the tag is removed from those photographs.

You can move the position of a Tag within the tree by dragging it to the position that you want and dropping it there. A menu will appear that gives you the option to Move the tag. This works from the left and right sidebar. A tag can only be in one place in the tree at a time.

You can set the Tag Properties by right-clicking on a Tag and selecting Edit Tag Properties. The Tag Properties allow you to change the name of the tag and the icon used in the "Tags" tree.

To select a different photograph as the tag icon, right-click on the photograph that you want to use as the tag icon and select "Set as Tag Thumbnail" from the context menu. Additionally you can use drag and drop to set the tag icon. Drag the images icon and drop it on the currently selected tag in the tag list.

##### Tagging Photographs

Before you can get the most out of &digikam;'s Tagging capabilities, you must first tag your photographs. There are two methods of tagging photographs. Once you have identified the photographs that you want to tag you can either drag and drop them onto the Tag in the "My Tags" tree or, by right-clicking on the selected photographs in the Image Window, you can use the Assign Tag menu to select the Tags you wish to set.

You can label a photograph with as many tags as you like. The photograph will appear when you select any of the tags that are set against it. This way you can set a tag for each person in a photograph, as well as the place the photograph was taken, the event it was taken at, &etc;

###### Tagging Image with context menu, or with drag&drop from either sidebar

Once you have tagged a photograph, the tag name will appear under the thumbnail in the Image Window.

You can remove a tag from a photograph by right-clicking on the photograph and using the Remove Tag menu. This menu will only show those tags that have been set on this photograph.

#### The Timeline

The timeline view shows a timescale-adjustable histogram of the numbers of images per time unit. A selection frame moves over the histogram. To select a time frame just click into the lower square of the selection frame where the time unit is indicated. That will show all corresponding images in the main window.

In the field right below you can enter a title and save your selection. It will then appear in the list field at the bottom.

##### The Timeline View in Action

#### Searches View

##### The Quick Search

Quick Search is a little box in the status bar and provides you with a simple means to search all data fields in the album library with a single query. You can enter any arguments in the Search text field and it will be used to determine the results. For instance, you can enter the string 'birthday' to search the complete album library for occurrences of the word 'birthday' in all photograph descriptions, or '05.png' to search for a specific image file name '05.png' (no escaping as in regexpressions needed).

Search Properties:

- searches are case insensitive

- blank separated search terms are boolean AND combinations

- special characters are literal and not interpreted ( . * ? / &etc;)

- include all elements of the database: names, rating, keywords, tags, albums, collections, dates (and more in the future)

The Quick Search really works intuitively. If you want to search images from a certain date, you can simply type `2005`, but it is even possible to search for a certain month. Just enter the name of the month in your local language. If it is Dutch, you can enter `Maart`, to see the images of March. The combination of 'Maart 2006' means 'Maart AND 2006' and therefore is equivalent to '2006 Maart'. Or look for 'Maart 2007 cr2' to find all RAW files of March 2007.

Next to the search box is a little LED that turns green if the search has results. Just click on it to reset the filtering and show all images again. If the search is not succeessful, the LED turns red.

###### Quick Search Tool Dialog in Action

##### Searches proper

The more sophisticated search tool is a tab on the left sidebar (binocular icon). If you open it, you will be presented with a simple search box the works as described above, except that you can save this search as a live folder that always filters for what you entered as search criteria. When saved, the filter will appear in the list.

When you are satisfied with your selection, click on the Ok button, and the search will be carried out, and the results displayed in "My Search" view from the main window. The Save search as text field will be used to label your query in "My Search" list. If you want to modify your selection after performing a search, simply right click on the item from "My Search" view and select an option from the pop-up menu.

###### Quick Search Tool Dialog in Action

If you select Edit Search, the search form will re-appear, containing your previous search information. If you select Edit as Advanced Search, the advanced search tool dialog will be come up to modify your previous search information using more elaborate search rules. See the The Advanced Search Tool section for more information.

If you want to remove an existing search from the list, just select Delete Search from the pop-up menu.

###### Search View from Main Window

##### The Advanced Search Tool

Advanced Search tool provides an extended search form with a wealth of search parameters, which can be used to search in specific fields of the &digikam; albums database.

The Search Rules list is used to set all options to process a search query in the albums database. All rules are listed vertically and separated by an operator. An option can be added or deleted to the list using Add Search Group/Remove Group. Each option can be combined with another one using Meet all.. or Meet any... or one of these... At least one... logical operators. Thus, one can construct searches of the type "AND NOT".

#### Fuzzy Searches/Duplicates

&digikam; characterizes every image by a legthy number using a special technique (Haar algorithm) that make it possible to compare images by comparing this calculated signature. The less numerical difference there is between any two image signatures, the more they resemble each other. This technique has three implementations

- Similar items: This is a drag&drop zone where you can drop any image to find a similar one. A threshold can be modified in order to narrow down or enlarge the resulting selection. Drag an image from anywhere over the fuzzy search icon in the left sidebar, it will open and you drop it there.

- Sketch: free hand color sketching: draw a quick sketch and &digikam; will find corresponding images. Again a threshold can be set.

- Duplicates: after &digikam; has scanned all collections you will find a list of duplicates here. It's up to you of course to decide what to do with them. From the menu Tools Rebuild all fingerprints... you can initiate a total rebuild of the image signatures (may take hours if you have a large collection, an estimate is 2 hours for 10'000 images) or from the bottom you can just rescan, which is much faster. Find duplicates will do just that, but it will take a long time too as it has to compare every image with any other image. Fortunately, you can refine your search by albums and/or tags.

##### Fuzzy search for similar image

##### Find duplicates while restricting to an album

#### Map Searches

This tab provides an intuitive map search tool based on the marble widget. You can zoom in and out with the mousewheel by either scrolling it or hold and drag it. Pan by holding down the left mouse button. Press the &Ctrl;left mouse button to pull-up a square as indicated. All images falling within the coordinates of that square will be filtered and shown (provided your images have been geo-coded of course).

In the box below you can enter a name for your geo filter. It will be added to the list view below for future reference, it acts as a live geo folder.

##### The Map Searches tab

For higher resolution maps choose "More Info"

### The &digikam; Light Table

&digikam; features a light table in a separate window to easily compare images. It works with all supported image formats including RAW files.

Select one or several images in any view from the main window, call &Ctrl;L Place onto Light Table from the context menu. The selection will be added to the light table, and its separate window will open. When you are back to the &digikam; main window you can quickly access the light table with L Tools Light Table .

From the thumbbar drag & drop images to the left and right comparison pane below. A little arrow will indicate which copy is shown in which pane. If you choose Synchronize Preview from the toolbar, any zoom and panning in one window will be synchronously executed in the other pane, so that you can compare the same areas of two images.

Another mode is better suited for quickly culling from a series of images. If you choose Navigate by Pair from the toolbar, the first two images will be automatically inserted into the comparison panes. Click on any thumbnail to make it the left side preview, the adjacent thumbnail to the right will be inserted into the right pane. That make it easy to sift through a series of similar images.

Of course, the usual delete actions work from the light table directly as well as F4 File Edit... .

All image information from the main window right sidebar is available for each of the two previews in the light table. This makes it easy to link visual differences to exposure data for example.

In the lower right corner of each pane there you find a built-in panning action (crossed arrows). Click on it and keep the &LMB; pressed to pan across the image (in synchronous mode both images will show the same viewing port).

Zooming works the same as in other views: use indifferently the zoom slider below the panes or &Ctrl;scroll wheel to zoom in and out, with both images when in synchronous mode.

#### The Light Table in Action

&doc-sidebar;

### Digital Asset Management (DAM) with &digikam;

Build a system to organize and find your photographs

- A case for doing DAM with &digikam;

- Build the archive: Folder organization, physical layout as information

- Automatic metadata generation

- Rating/Ranking

- Tagging, Keyword assignment

- Captions/Comments

- Geolocation (geo-tagging)

Protect your authorship and copyright/left

- Digital Watermarking (DW)

Protect your images from data corruption and loss

- Physical deterioation

- Logical errors

- Human errors

- Common myths dispelled

- Make your budget: Data size, required storage volume estimation

- Back it up, backup, backup, recover!

- Preserve your images through the changes of technology and owners

- Best practice: Data protection

A typical DAM workflow

#### Introduction

...in the end, photographs need a lot of care. I hope it's you who said this.

Can you find your digital photographs when you need them? Or do you spend more time sifting through your hard drive and file cabinets than you would like? Do you have a systematic approach for assigning and tracking content data on your photos? If you make a living as a photographer, do your images bear your copyright and contact information, or do they circulate in the marketplace unprotected? Do you want your future grandchildren to admire your photographs you have taken yesterday? How do you ensure backup and the correctness of your data? How to prepare to change your computer, your hard disk, the software, the operating system and still manage to find your pictures or movies?

What is digital asset management - apart from a buzz word? Digital Asset Management (DAM) refers to every part of the process that follows the taking of the picture, all the way through the final output and permanent storage. Anyone who shoots, scans or stores digital photographs is practicing some form of DAM, but most of us are not doing so in a systematic or efficient way.

We present a tool, a plan and practical advice on how to file, find, protect and re-use photographs, focusing on best practices for digital photographers using &digikam;. We cover downloading, renaming, culling, converting, grouping, backing-up, rating, tagging, archiving, optimizing, maintaining and exporting image files.

A generic definition:

> "Digital Asset Management ingests, indexes, categorizes, secures, searches, transforms, assembles and exports content that has monetary or cultural value."

And since we're at it another important one:

> Metadata is defined as data about data. Metadata is definitional data that provides information about or documentation of other data managed within an application or environment.

In our context here it stands for all information about a photograph.

&digikam; with its libraries and plugins is a unique and comprehensive tool to cover most of DAM tasks, and it does it fast and transparently. Based on open standards on all fronts it will not confine you to a platform or application, rather it puts you into a fast track to manage and find your photographs and to move on if you so please to any other platform, application, system without losing any of your work be it as an occasional user, enthusiast or professional.

The one thing that differentiates the archiving capabilities of film vs digital is that with digital you can make as many new originals as you want. With film you only have one original. All copies will have a slightly lower quality, and both originals and copies are more or less slowly aging and disappearing. The only way to keep it "forever fresh" is to make a digital copy of it. And that is also the only way to protect it from all hazards.

Even if digital media today may last shorter than film it is just up to you to make new copies every year, 5, 10 years or whenever necessary, and to always keep at least 2-3 copies of the files, preferably in different physical locations. You never had that opportunity with film. It could always be damaged in a fire, floods or similar - or even be stolen. The good and bad news then is this: if you lose digital images/data it is only your own laxity.

#### Build a system to organize and find your photographs

Themes: hierarchy, tags, rating, captions, geolocation, date, albums, filenames, versioning, exporting

I dare-say if you have more than 1000 photographs on your computer in no-DAM fashion it takes you too long to find any particular image. And if you don't know how many images are in your files you're surely not using &digikam;. The dual approach to store metadata in a database and in the image files guarantees ultra fast searching and secure archiving freely accessible to other applications, platforms and formats.

But as much as there is no such thing as a free lunch, there is no free cataloging or DAM - those who spend the initial time of building a systematic method of their own will be better off as time passes and the number of photographs multiplies. The ROI (return on investment) of DAM has been estimated in different studies to be better than 10. Keep in mind to be `concise, plan for the future (30-50y), do it once`. The upcoming semantic web will totally integrate into and add value to a DAM environment.

##### A case for doing DAM with &digikam;

&digikam; provides a number of methods to classify photographs: filenames, albums, collections, date + time, tags, rating, GPS position and captions. As if this was not enough, in the KDE4 version of &digikam; you can search many standard metadata items like camera model, lens, coordinates, image size and many more. Metadata categories as listed here are in fact different 'views' of your photo library. Combining these views is the very powerful method to narrow down the search for a file and to find it quickly. Imagine having 800 photos of your loved one. Searching for 'Mary', having more than '***' rating, shot in 'France' will surely leave you with very few candidates. In terms of selection criteria for a DAM system, &digikam; fares very well in terms of completeness, versatility, speed, scalability, accuracy and openness.

The key thing to remember is that you don't know how you or somebody else will try to find an image 2 years ahead of our time. You will remember past events in a different context, it's a fact of life. So if can narrow down your search by remembering place or time or camera or theme or rating or owner you stand an infinitely better chance to find it quickly than by just one of those criteria or none. At the beginning, at the time of taking a photograph, all metadata is in your head (except for the EXIF data). If you do not transcribe some of it into your DAM system, it will be lost eventually as much as every event fades into oblivion over time.

One distinction has to be interjected here between `private` and `public metadata`. One could say that all file-embedded attributes are potentially public since the images may be exported, sold, and copied to other places and people. On the other hand all non-embedded metadata in the database can be considered private as they stay in the database and go nowhere else. By adjusting &digikam;'s settings accordingly you can control what kind of data remains private and what will be embedded and eventually become public.

##### Build the archive: Folder organization, physical layout as information

The first thing to do and to know before you put anything onto your system is a to build an information structure (as opposed to data structure). Your image files have to be somehow organized within the computer, you have to decide if others should have access to your photographs (sharing), if you put them on a dedicated drive, on a network drive &etc; Keep in mind that you have to migrate one day onto some bigger volume.

The organization should be simple, unified and scalable, and it should be independent of the storage medium on which you host them. Do not make the folders too small, several thousand images in one folder is not too much to ask for, but keep them small enough so that they can fit into a backup medium like a DVD 4.7 or 9.4 GB for double sided ones. Remember that the archive will grow all the time! The concrete type of structure depends on your use case of course: Lets take a simple yet frequent example: you are a casual photographer taking pictures of your private life, your family, holidays and so on. It could be efficient to create a structure based on years plus some holiday and export containers. It could look like this:

>     2006
>     2007
>     2008
>     Holidays
>       - A
>       - B
>       - C
>     Export
>     Fun stuff

Maybe you'll be happy with this structure. Holiday pictures can be quickly found by its location (unless you go to the same place every year), the rest will be organized by date. If you shoot enough pictures you want to create sub folders below the years as months ⪚ 2008-01, 2008-02 &etc; 'Export' would be a container for images to print or to put onto a website.

The more professional photographer will have very different needs as there will be versions of photographs, archives, workflows, a constant influx of images of diverging themes, and a large quantity of everything. Within 10 year you'll have 95% archives and 5% work space files and you don't want to organize your structure around content!

The consideration are these:

- what kind of files go together? Segregation of file type makes batch processing easier. Keep new and old files separate.

- How can you make that structure scalable?

- Segregation of original and working files makes it easier to allocate the backup strategy and migration. You will always know if you look for an original or a derivative.

TBC

##### Automatic metadata generation

How to go about all this metadata business? Firstly, there are already a lot of `automatically generated metadata`: EXIF data and Makernotes. If you have configured &digikam; with your identity section all imported images will be imprinted with this data set which includes copyrights, all automatic. If you have a GPS track recorded in parallel to your taking the photographs, you can geolocate those images in a single action using the Geolocation plugin. Even if you brought back 1000 images from a shooting session, so far you'll not have spent more than 10 minutes to do all that. And by now you have all camera settings of every shot, lens data like zoom, focus, aperture &etc;, date and time, shooting location, copyrights, authorship, program used, and more. Not bad, isn't it? But we could have done more during the importing, we could have changed the file names to include the date, or place or theme, we could have changed the format to a lossless 16 bit per channel format, we could have automatically separated JPEG and RAW files into their folders. I actually recommend to auto-rename to match an event, a place or a theme. &digikam; provides all date/calendar related grouping so that there's hardly a need for coding the date into the file name. Unless you'd like to do just that to browse your albums with another application that is not calendar savvy. You will buy a new camera one day or you have a second one already, sooner than you believe. The numbering scheme of that new camera will start over at typically IMG_0001.JPG again, creating identical file names to the ones you have already if you do not rename them. By renaming you lessen the chance of inadvertently overwriting them at a later date. Keep the new names clean, use alphanumerics, dashes, underscores and a single period prior to the file extension.

I also recommend to switch-on the 'save metadata' options in the &digikam; settings page for metadata. This will ensure that EXIF and IPTC data is written into the file. If you forgot to do that you can always catch up by copying the metadata in the database to the files in one go (from the album menu).

Now we have a lot of stuff already in our database, but what if I need to change some of it? &digikam; provides a metadata editor for a selected number of attributes, the most important ones of course.

The real works begins here as we will apply tags, captions and a rating to every photograph. Of course, all images requiring the same attribute can be treated as a selection in one action. Lets start with rating or ranking. It's best to start with ranking because for further work you can concentrate on the good shots.

##### Rating/Ranking

A ranking systematic is implemented in &digikam; by the 5 star rating tool. In fact there are 6 levels, zero through five stars (*) can be attributed (when saving them into IPTC metadata a translation of levels ensures compatibility with other programs). Rating is rapidly applied with &digikam; using keyboard shortcuts or the mouse on single photographs or whole selections. The rating can then be entered as a search criterion or directly from the status bar quick filters. However, before you start attributing stars everywhere take a moment to establish personal criteria for ranking. Best practice is to write down your personal match of stars to some qualitative expression, that will define what you actually mean when giving 5 stars. Generally there should be much less images rated with increasing star assignment. A ratio of 3-10 between each level has proven useful. That will get you quite far in distinguishing your rating pyramid. Say, you choose a ratio of 7 between levels. For every 5 star image you'll then have 7 4 stars, 49 3 stars and so on, resulting in almost 20000 pictures. Amazing? Yes, and 16807 of them you didn't have to rate at all! You even can define a different rating scheme depending on the kind of use, 2 stars for commercial use, may mean something else than 2 stars holiday photos. It is also a good practice to define a neutral rating, everything below is actually a negative rating. This will help you culling and thinning your collection very efficiently. Or you could define purposes to ratings, say 0 stars for 'can throw away', 1 star for images in quarantine (decide later), 2 stars for gallery export, 3 stars for printing, 4 stars for selling, 5 stars for 'have to work on', as you please. It must suit your needs. The following table illustrates a possible evolution for a professional photographer using a ranking ratio of roughly 7 over the next 12 years. It is evident that the good shots can be easily found, even within millions of photos.

Ranking

Lets continue with tags (or keywords as called by other applications, or categories, they are all synonymous).

##### Tagging, Keyword assignment

Tags are a hierarchical labeling system that you create as you add to it. The important thing to do is to create a system that suits your needs and habits. Are you a (semi)professional who wants to sell photographs to agencies, do you want to publish on a web gallery, or are you just the occasional amateur managing the visual family memory? For all these different use cases you want to design a tag structure that is adapted to it. If you configure it so, &digikam; will write the whole hierarchy into IPTC fields so that they can be used by your photographic agency using a different application of to automatically create title and caption for web exports. In any case it will serve you well to quickly find a specific picture again.

The hierarchy will provide you with automatic groupings. For example, if you start a typical private use hierarchy with 'Activities', 'People', 'Places', 'Themes' and 'Projects' on the top level, everything you tag with a sub-tag of these will be grouped together into a virtual album. &digikam; has a dedicated view in the left sidebar for these virtual albums. But it comes even better! As you continue adding sub-tags into the hierarchies, not only will you be able to search and quick-filter for them, the right sidebar tag filter allows you to select combinations of tag groups. Lets say in the left sidebar tag panel you select the virtual album 'People' and you have 12 different tags for people in there, then you can combine it with the right sidebar and just choose 'Peter', 'Paul' and 'Mary' out of the 12.

In the long run you will not remember the details of your pictures and their subject (essentially the metadata in you brain will break down). It is therefore paramount that you `choose general and generic categories`. You will aways remember that a particular shot was set at a river bank in a country or continent (-> river, continent), but you'll have forgotten which river it was. Instead of only tagging it with 'Okavango' you tag it with river/Africa or river/South Africa. The details you can either put into a tag as well or into the captions. A trick may help you: How would you search for that river with an Internet search engine? That's the way to go!

Another categorization might be task-oriented as in 'print jobs', 'web export', 'personal', 'galleryXYZ', 'clients', 'slideshow' &etc; Create groups as you need them but not more, you should be able to remember by heart the top level tags at least, otherwise the differentiation will become useless. Don't forget that you have all the other attributes to narrow down the search. The right sidebar tag filter combines with any view of left sidebar (albums, calendar, timeline, tag and search).

When you import cataloged images from other sources having embedded tags already, &digikam; will automatically create the trees for you, respectively insert it into the right place. Rearranging the hierarchy within the tree is no problem, you can do that easily by dragging and dropping a sub-tree to another place in the hierarchy. The changed tags will be updated as &digikam; ripples down the branches.

The graphics here shows how different metadata overlap. This is a very coarse representation, as each block of metadata will in itself be subdivided into many sections. File names and calendar data are properties of all images.

Ranking

Enough of tags - lets move on to captions or comments, the third major tool for metadata cataloging.

##### Captions/Comments

This is already the 4th kind of metadata we present here. What is the distinction of captions compared to tags (comments can be used synonymously, but the IPTC vocabulary stipulates the term 'caption'), keywords? Where tags owe to a hierarchical and generalized description, captions are the opposite: prose description, details, anecdotal stuff. Tags foremostly serve the finding, retrieval and grouping of assets, whereas captions shall entertain, inform, touch the beholder. Naturally they can also be used to filter the catalog, but this is just a byproduct. Captions are to remember the story, the event, the emotions, it's what makes photographs much more interesting to look at, captions put photographs into a context and meaning. If the pictures are an aesthetic statement, caption should be the emotional and informational complement.

You rarely want nobody to see your photographs. You rather want to share them with friends, your family, other photographers, agencies, put them onto the Internet. And don't tell me you're not interested as to how your photos are being received!

So you might have to most beautiful portrait, sunset or landscape and nobody seems to care. Why is that? Look at some good photographs yourself without reading the title, comment or background information. How many of you are interested in depth of field, exposure time, white balance &etc;? Some, of course. But anybody will be interested in the story the pictures tell, you want to remember a photograph, meaningless images bombard us too much anyways. You have to give the viewer something that explains it all.

Lets look at this panorama. From far it is not even a nice beach panorama. If you go closer you start to see some details, people, the space.

Ranking

And now I tell you that this is the Allies landing site "Omaha Beach" in the French Normandie 60 years after the disembarkation. Wow! One starts to dream, have associations, memories, the historical time span is present, you may hear the silence. The caption has totally reframed to perception of this panorama.

For others to appreciate your photographs, the title is probably more important than the image itself for the interest it creates. When you show pictures, tell a story. Remember that the key is to convey the meaning to viewers, to help them understand what you understand about the subject and what moved you.

- let people know what you understand about the subject, why you love it

- create a red line between the photographs

- oppose or relate them to different epochs

- take notes shortly after shooting to remember

- contemplate, research, watch, and talk - but mostly listen.

- it's okay if the image is less than perfect because it has the strength to stand on its own merit described in the caption.

With &digikam; you can enter unlimited amounts of text using internationalized alphabet (UTF-8) as caption. You can enter it for a selection of photos at the same time. KDE even provides a spell checker. When you export images to web galleries, the captions will be exported at choice into either/or/and caption/title of the web gallery system, no need to re-write the story for publishing.

##### Geolocation (geo-tagging)

Do you still remember the times before GPS? When you would find your way to another city without navigation system? Wasn't the earth a dull blue ball before GoogleEarth? Well then, with images, the train of spatial representation is running at cruising speed alright.

A few cameras have a GPS receiver built-in, the images come tagged with 3-dimensional coordinates. And with almost any GPS device you're able to extract a trace (of course the receiver needs to be switched-on and carried with you whilst taking the photographs, and for good matching the camera time must be accurately set) and save it onto a computer. You have to store it in gpx format, that's easily done with gpsbabel, gpsman and other tools. You then can automatically match a whole bunch of photos with that track using &digikam;. The coordinates are written into the JFIF part of JPG files (settings choice) and into the database. The KDE4 version will enable searches based on locations and coordinates, you can create virtual albums of geographical areas! In the right sidebar under the metadata tab you'll find your image located on a local zoom of the world map. A further click brings on anyone of several mapping services on the web, zooming in on details. Even if you don't have a GPS trace you can geo-tag multiple images with a geo-editor. Just navigate on the map to the spot of shooting and click to fix it as a geo-tag.

e.g. conversion of a Garmin track with file name 'xyz':

>     $ gpsbabel -w -i mapsource -f xyz.mps -o gpx -F xyz.gpx

The possibilities of exploiting this geolocation are already innumerable and will become pervasive in the future. I'm sure one day not too far away we can revisit in a virtual reality our travels through geo-tagged pictures. The &digikam; features include exporting to kml files that can be opened by GoogleEarth (which in turn will show the photos on their shooting site), exporting to gallery2, picasaweb, flickr &etc; with GoogleMaps viewer and more.

#### Protect your authorship and copyleft/right

Themes: watermarking, IPTC and XMP authorship data, export size

This will be the last chapter and step to mark your digital library with authorship, ownership and copyright or -left information. More than in 'the good(?) old days' of paper copies, the ubiquitous Internet makes it just too easy to 'steal' a picture from a web site. At the very least, for all images that will be exported and/or published in any form, the authorship and copyright information should be part of their metadata. Nothing more simple to do with &digikam;: you can setup the default identity, and any images ingested be &digikam; will be automatically informed. I put copyleft in the title for a reason (citation from wikipedia):

> "Copyleft is a play on the word copyright and is the practice of using copyright law to remove restrictions on distributing copies and modified versions of a work for others and requiring that the same freedoms be preserved in modified versions.

> Copyleft is a form of licensing and may be used to modify copyrights for works such as ... music, and art. In general, copyright law allows an author to prohibit others from reproducing, adapting, or distributing copies of the author's work. In contrast, an author may, through a copyleft licensing scheme, give every person who receives a copy of a work permission to reproduce, adapt or distribute the work as long as any resulting copies or adaptations are also bound by the same copyleft licensing scheme. A widely used and originating copyleft license is the GNU General Public License. Similar licenses are available through Creative Commons - called Share-alike."

And here follows a description of what should be supplied to &digikam;'s setup page as information:

`Author` (synonymous with Creator and By-line): This field should contain your name, or the name of the person who created the photograph. If it is not appropriate to add the name of the photographer (for example, if the identity of the photographer needs to be protected) the name of a company or organization can also be used. Once saved, this field should not be changed by anyone. This field does not support the use of commas or semi-colons as separator.

`Author title` (synonymous with By-line title): Linked to Author. This field should contain the job title of the photographer. Examples might include titles such as: Staff Photographer, Freelance Photographer, or Independent Commercial Photographer. Since this is a qualifier for the Author field, the Author field must also be filled out.

`Credit` (synonymous to Provider): Use the Provider field to identify who is providing the photograph. This does not necessarily have to be the author. If a photographer is working for a news agency such as Reuters or the Associated Press, these organizations could be listed here as they are 'providing' the image for use by others. If the image is a stock photograph, then the group (agency) involved in supplying the image should be listed here.

`Source`: The Source field should be used to identify the original owner or copyright holder of the photograph. The value of this field should never be changed after the information is entered following the image's creation. You should consider this to be a write-once field. The source could be an individual, an agency, or a member of an agency. To aid in later searches, I suggest to separate any slashes '/' with a blank space. Use the form 'photographer / agency' rather than 'photographer/agency.' Source may also be different from Creator and from the names listed in the Copyright Notice.

`Copyright Notice`: The Copyright Notice should contain any necessary copyright notice for claiming the intellectual property, and should identify the current owner(s) of the copyright for the photograph. Usually, this would be the photographer, but if the image was done by an employee or as work-for-hire, then the agency or company should be listed. Use the form appropriate to your country. For the United States you would typically follow the form of © {date of first publication} name of copyright owner, as in 'copr 2005 John Doe.' The word 'copyright' or the abbreviation 'copr' shall be used in place of the © symbol as ASCII characters only are allowed. In some foreign countries only the copyright symbol is recognized and the abbreviation does not work. Using something like (c) where the parentheses form a partial circle is not sufficient. For additional protection worldwide, use of the phrase, 'all rights reserved' following the notice above is encouraged. In Europe you would use: Copyright {Year} {copyright owner}, all rights reserved. In Japan, for maximum protection, the following three items should appear in the copyright field of the IPTC Core: (a) the word, Copyright; (b) year of the first publication; and (c) name of the author. You may also wish to include the phrase 'all rights reserved.'

Whereas it is paramount to fill-in the author and copyright sections, they represent no protection against fraud. Anyone with a bit more than basic computer knowledge is able to delete or modify image embedded metadata. The solution to this problem is called 'digital watermarking'. To private persons this might be of little interest for the majority of photographs, but for professionals ans semi-professionals this protection is really important.

##### Digital Watermarking (DW)

Digital Watermarking refers to an invisible digital watermark that is being impressed on photographs as an element of digital rights management (DRM). The watermark contains the same information of authorship and copyright as described above, but the metadata is encrypted and saved in the actual image data (as opposed to the metadata section which is a separate section within the image file). This invisible imprint has holographic properties so that modifications done to an image (size, color, crop, up to a certain limit) will not destroy the copyright information. Only when an image is resized to a very small fraction like a thumbnail will the embedded information be lost, but then the image is of no value anymore to the copyright infringing party.

The digital watermark will be unique per image. &digikam; will provide a plugin for DW in the near future that features batch processing.

#### Protect your images from data corruption and loss

Themes: disk errors, disk failures, power surges, ECC, transmission errors, storage media deterioration, recovery, redundancy, disaster prevention, lifetime, temperature, data size, common myths

##### What are then the main factors of digital data loss?

Of course we're not talking about losing CDs on the road or in a fire - that kind of loss is just the same as traditional paper copies or negatives. We are talking about problems with the so called "New Media".

Problems with digital data can roughly be categorized into the following areas of concern:

1. the physical deterioration of the media (all media deteriorate at different time scales)

2. undetected transmission errors during data transfer

3. the lack of support for long-date, undoubtedly proprietary, digital formats

4. ancient hardware.

Kroll Ontrack, the worlds largest data recovery firm, have some interesting statistics on what actually causes data loss.

Cause of data loss | Perception | Reality
Hardware or system problem | 78% | 56%
Human error | 11% | 26%
Software corruption or problem | 7% | 9%
Computer viruses | 2% | 4%
Disaster | 1-2% | 1-2%

So let us analyze those cases step by step!

##### Physical deterioration

###### CD, DVD, optical drives

Physical deterioration of the media happens more rapidly with paper and CD-Rs than the average of film. Yet while film lasts longer (sometimes decades longer) than other forms of media, the right kind of backup of digital media never loses anything. Film decays - digital 1's and 0's do not, and film starts to decay the moment it's created and developed. It will never have the same color, contrast, &etc; that it did have a moment before. Digital doesn't do that. However, digital is susceptible to corruption! And yes, physical media such as floppies and magnetic hard drives are also susceptible to the decay of the medium, just like CDs are. They just last longer.

To combat the problem of CDs/DVDs, they need to be properly cared for and not trusted for more than a few years. Thankfully you can purchase archive-quality CDs and DVDs which last longer, though they are much more difficult to obtain and are much more expensive. There are offers out there for gold-plated DVDs, $2 a piece claiming 100 years storage life (if you care to believe it).

CD/DVD disks may become unreadable, but you can reduce the risk using good disks and a good recorder, and storing them in a correct way. The best DVD recorders are not much more expensive than the cheapest, but they write in a much more reliable way. It's a matter of choosing the right one.

Essentially, CDs and DVDs are very prone to errors, even in a freshly written state. That's why they are heavily protected with a checksum mechanism (75% of data are effective data, the rest is formatting and checksum overhead). But even with that massive amount of protection they will suffer deterioration from chemical aging, ultra-violet exposure, scratches, dust, &etc;

For damaged CDs and DVDs, there is an inexpensive program called IsoBuster from which will do seeming miracles on CDs and DVDs. It runs on Windows and &Linux;; but not (yet) on Macs. Similarly, there are applications designed to get data from damaged floppies, hard drives, flash media such as camera memory and USB drives, and so forth.

Optical media: Blu-ray disks seem to win the format war against 'HD DVD'. A dual-layer Blu-ray disc can store 50 GB, almost six times the capacity of a dual layer DVD at 8.5 GB. Everything that has been said about CDs/DVDs applies to Blu-ray disks as well.

Best practice:

Burn them slowly with a good recorder on archive quality media in an open, non-proprietary format, read the data back to verify, label them with some descriptive text + date & author, lock them away where it is clean, dark, animal safe and dry. And do not forget to copy them over to the next generation of media before you throw away your last piece of hardware or software able to read them.

###### Hard disks (hard drives, HDD)

Disk manufacturers keep their statistics to themselves. A manufacturer guaranty buys you a new disk, but no data. Google for one has done a large scale study on HDD failure mechanisms: Disk Failures study

In a nutshell: Disks run longest when operating between 35°C and 45°C, at lower temperatures the error rates increases dramatically. Controller parts (electronics) are the foremost sources of failure, SMART does not diagnose any of this. Some SMART errors are indicative of imminent failure, in particular scan errors and relocation counts. Lifetime expectancy is 4-5 years.

But all depends much on the real use case and some luck. For example I have a Fujitsu notebook that is running 24/7 since 1998, almost ten years without the slightest hick up. Just luck? In general and contrary to intuition or ecological considerations, running a hard drive permanently results in a longer lifetime than switching it on and off all the time. It has even been reported that aggressive power management spinning down the drive can harm it quickly. Making it working hard shortens the lifetime somewhat. The worst factors for HDD probably are vibrations, shocks, and cold temperatures.

If your disk is making weird noises, normal file recovery software isn’t going to work. Do a quick backup if that is going to happen to you. (Use dd utility if possible, not a normal file backup since dd reads in a smooth, spiraling stream from beginning to end and doesn't stress the mechanics). There are specialist companies that can recover data from otherwise destroyed drive, but they are costly, plan for 2000$ minimum charge.

###### Power surges

As much as 1% of all computers are affected by lightning and power surges every year.

(This is about total data loss due to power surges. Of course you can have the occasional data loss due to power loss before saving files. But those losses can normally be restored without major difficulty.)

You don’t have to wait for the next thunderstorm to be concerned about how a sudden fluctuation in electric power may affect your computer system. Recent statistics have shown that as much as 63 percent of all electronics casualties are due to power problems, and most computers are subject to two or more power anomalies a day. Since power surges or blackouts can occur anywhere and at any time, it only makes sense to protect your computer by investing in some sort of surge protection device.

###### How surges happen

A power surge occurs when the power line voltage increases over nominal values for more than 10 milliseconds. Sixty percent of all power surges are caused from within the home or office, generally when a device with a motor (such as a hair dryer, refrigerator, or water pump) shuts off and the power it was using is diverted elsewhere as excess voltage. The remaining 40 percent of power surges are generated by factors such as lightning, utility grid switching, line slapping, poor wiring, and so on.

While most average electricity-using devices are not affected by power surges, devices relying on computer chips and high-speed microprocessors are susceptible to serious damage. For your computer, power anomalies can result in keyboard lockup, complete data loss, hardware degradation, damaged motherboards, and more. Failure to protect yourself from the inevitable can result in a loss of both time and money.

###### Surge protectors

The most common defense against power surges is a surge protector or suppressor, a device that works by absorbing some of the excess energy and diverting the rest of it to the ground. These are usually found in the form of a power strip (one of those long devices that have six or so outlets and a single, grounded plug). Bear in mind, however, that not every power strip serves as a surge protector.

When selecting your surge protector, you want to be sure it is listed as meeting the UL 1449 standard, which guarantees a certain minimum of protection. You should also look for one that offers protection against lightning (not every one does) and provides insurance for equipment that is properly attached.

Because a power surge can follow any path to your computer, be sure that each peripheral connected to your system is protected. This includes your phone line or cable modem, as power can surge through these routes as well. A number of manufacturers are now producing surge suppressors that feature a phone jack for your modem along with the electrical outlets, while others have coaxial cable jacks for those who use a cable modem or TV tuner card.

If you have a notebook computer, you will want to carry a surge suppressor as well. A variety of suppressors designed specifically for notebooks are available, small in size and possessing both electric and phone outlets that make them ideal for use on the road.

###### Uninterruptible power supply (UPS)

While a surge suppressor will protect your system from minor fluctuations in the power lines, it won’t help you if the power should black out completely. Even an outage of just a few seconds can result in the loss of valuable data, so you might find it worthwhile to invest in an uninterruptible power supply.

Besides serving as surge suppressors, these devices automatically switch to battery power when a power outage occurs, giving you the opportunity to save data and shut down your system. Some models will even allow you to keep working until power is restored. When purchasing a UPS, be sure that it has the same qualities that you would seek in a surge suppressor, but also check out the battery life and included software.

Considering the potential risk to your computing system, ensuring its safety from power disturbances is a worthwhile investment. A quality surge suppressor will cost you upward of €20, a 500W UPS can be had for less than €40. It’s a small cost to pay for the peace of mind you’ll gain knowing your computer is well protected. In the very least pull all lines to your computer when you go on holidays.

###### Solid state drives: USB sticks, memory cards, flash disks

SSDs are mechanically more robust than HDDs and suffer much less on that front when they are plugged into the computer. But since they are mostly mobile devices, their exposure to drops, accidents and electrostatic discharges is much higher. So, for different reasons, SDDs are as likely to fail if not more than hard drives. Add the danger of theft and longevity and limited capacity, and SDDs will become prohibitive as permanent data storage devices.

One major cause for data loss (often recoverable) is the unsafe removal of SDDs from a computer. Before data is saved from a computer memory to any attached device, it remains for some time in buffers. In hard drives this means seconds at most, whereas with SDDs it can be tens of minutes. Therefore, before you disconnect a flash device, always activate data flushing through software (often called "safely remove device").

There is a new technology trend coming up, to replace hard drives with SSD flash drives. By 2010 they may be competitive in price to HDDs. Data retention is an issue with SDDs, it cannot be overwritten an infinite amount of times. SDDs wear in use. Wear then depends much on the location data is written, and how often it is written. &Linux; has developed a special driver avoiding writing to the same spot too often. But this is all premature information. Keep your eyes and ears open.

###### Magnetic media

Magnetic tapes are used in backup systems, much more in professional environments than in home use. Tapes have issues with data retention and changing technology, but they are safer in one aspect than CDs and DVDs: they are less exposed to scratches and dirt and writing deficiencies. On the other hand they are susceptible to magnetic fields. Throw a magnet next to a tape and it's gone! Tapes should be re-copied every 5-8 years, otherwise too many bits will fail and escape the checksum protection. The downside of magnetic tapes is often the recorder price and the restore time (20x longer than from HDD). Tape backup system have seen their best days.

##### Saveguarding against logical errors

###### Web storage services

Amazon Web Services includes S3 - Simple Storage Service. With appropriate configuration, you can mount S3 as a drive on &Linux;, Mac, and Windows systems, allowing you to use it as a backup destination for your favorite software. Google Shared Storage is another popular offer where one can store infinite amount of data.

It is expensive compared to hard drives at home - 40 GB cost $75 a year, 400 GB cost $500. And you have to transfer the images over the (a comparatively slow) Internet.

I think as a safeguard against localized data loss of the most essential images it's not a bad idea at all, but it is not a general backup solution, much too slow for that.

Picasaweb (Google), Flickr (Yahoo) and Foto-Community 23hq.com provide online storage services specialist on photographie. Their free space is limited to 1 GB and you don't want to have full resolution images online. But the pro-accounts offer more, in the case of Flickr, dramatically more. For a mere 25$ a year you get unlimited (sic! reality check needed here) space.

In terms of data retention the web space solution is probably pretty safe. Transmission errors are corrected (thanks to the TCP protocol) and the big companies usually have backup included plus distributed storage so that they are disaster proof within themselves.

###### Transmission Errors

Data does not only get lost from storage devices, it also gets lost when traveling inside the computer or across networks (although the network traffic itself via TCP is error protected). Errors occur on buses and in memory spaces. Consumer hardware has no protection against those bit errors, whereas it is worthwhile to look into such. You can buy ECC (error code correction) protected memory (which is expensive, granted). With ECC RAM at least the memory will be scrubbed for single bit errors and corrected. Double bit errors would escape that scheme but they occur too infrequently.

Transmission errors

This diagram depicts the transmission chain elements in a computer, all transitions are susceptible to transmission errors. The zfs and btrfs file system at least ensure the OS to disk path of data integrity.

The Byte Error Rate (BER) for memory and transmission channels is in the order of 1 in 10 Million (10E-7 bit). That just means that `1 in 3000 images has an error only due to transmission problems`. Now how dramatic that is for an image is left to chance, it could mean that the image is destroyed or that a pixel somewhere changed its value, due to the compression used on almost all images one cannot predict the gravity of a single bit error impact. Often one sees some partial images instead of the full image.

The worst of all that is that nobody tells you when a transmission error occurs, not your hardware. All those glitches go down unheard until one day you open the photograph, and to your surprise it's broken. It is quite worrisome that there should be no protection within a computer, nobody seems to have thought of it. The Internet (TCP protocol) is much saver as a data path than inside a computer.

Flaky power supplies are another source of transmission losses because they create interference with the data streams. With normal files systems those errors go unnoticed.

Expected error rate increasing with complexity

Even if you are not overly concerned today with transmission problems, have a look into the future at illustration. Already in 2010 we'll see thousands of errors per year!

###### 'Oracle' or 'Rising Sun' at the file system horizon?

ZFS from Sun Microsystems seems to be one of two candidates to deal with disk errors on a low level, and it is highly scalable. It is Open Source, heavily patented, comes with an GPL incompatible license, and is available on Solaris and Leopard. Let us hope that it will soon be available for &Linux; and Windows (article).

This is for the courageous ones. Fuse ZFS

Oracle has also started an initiative with its btrfs file system, which still is in an alpha stage. It employs the same protection technique as zfs does, and it's available on &Linux;, although it is not yet part of the stock kernel.

##### Human errors

###### Theft and accidents

Do not underestimate it! Those two factor account for 86% of notebook and 46% for desktop system data losses. For notebooks, theft counts for 50% alone.

###### Malware

Data loss due to viruses is less grave than common wisdom make you believe. It accounts for less damage than theft or re-installations, for example. And it is limited to Microsoft OS users. Apple users experience very few viruses and under &Linux; they haven't been around for quite some time now.

###### Panic is a factor in data loss

Human error, as in everything, is a major problem in data loss. Take a deep breath and stop! Panic is a common reaction, and people do really stupid things. Experienced users will pull the wrong drive from a RAID array or reformat a drive, destroying all their information. Acting without thinking is dangerous to your data. Stop stressing about the loss and don’t do anything to the disk. Better yet, stop using the computer until you have a plan. Sit down and explain you plan to a laymen or better, laywoman. You will be amazed how many stupid ideas you'll discover yourself in such an exercise.

If your disk is making weird noises, normal file recovery software isn’t going to work. Do a quick backup if that is going to happen to you. If the drive is still spinning and you can’t find your data, look for a data recovery utility and backup to another computer or drive. (Non-&Linux; users: Google for "free data recovery software" for some options, including one from Ontrack). The important thing is to download them onto another drive, either on another computer, or onto a USB thumb drive or hard disk. It is good practice to save the recovered data to another disk. dd is your friend on *nix systems.

##### Common myths dispelled

I'd like to dispel some common myths:

- Open Source file systems are less prone to data loss than proprietary systems: Wrong, NTFS is rather a tiny notch better than ext3, ReiserFs, JFS, XFS, to name just the most popular file systems that often come as default FS with distributions. A brilliant article about it is here: link

- Journaling files systems prevent data corruption/loss: Wrong, they only speed up the scan process in case of a sudden interrupt during operation and prevent ambiguous states. But if a file was not entirely saved before the mishap, it'll be lost.

- RAID systems prevent data corruption/loss: Mostly wrong, RAID0 and 1 prevent you from nothing, RAID5 can prevent data loss due to disk-failures (but not from disk or file system errors). Many low-end RAID controllers (most mother board controllers are) don’t report problems, figuring you’ll never notice. If you do notice, months later, what is the chance that you’ll know it was the controller’s fault? One insidious problem is corruption of RAID 5 parity data. It is pretty simple to check a file by reading it and matching the metadata. Checking parity data is much more difficult, so you typically won’t see parity errors until a rebuild. Then, of course, it is too late.

- Viruses are the biggest thread to digital data: Wrong. Theft, and human errors are the primary cause of data loss.

##### Make your budget: Data size, required storage volume estimation

Digital camera sensors are 1-2 aperture stops away from fundamental physical limitations. What I mean is this: as technology evolves, there is a natural limit to its progress. Sensitivity and noise characteristics for any kind of light sensor are not far from that limit.

Today's cameras tend towards 10 mega pixels sensors, although this resolution is already too high for compact cameras and deteriorates the end result. Given the sensor size and quality of optics, 6 mega pixels are optimum for compact cameras. Even DSLR cameras run into their limits at 10-12 mega pixels, for higher resolutions one has to go for full frame sensors (24x36mm) or even bigger formats.

So, taking into account the manufacturer mega pixel propaganda it seems save to say that the bulk of future cameras will see less than 20 mega pixels. This gives us an estimation for the necessary storage space per photograph in the long run: <15 MB per image. Even if file versioning will be introduced (grouping of variations of a photograph under one file reference), the trend is to implement scripting of changes so that a small overhead will be recorded only and not a whole different image per version. With faster hardware this concept will see it's maturity quite soon.

In order to estimate the amount of storage space you have to plan for, simply determine the number of photographs you take per year (easy with &digikam;'s timeline sidebar) and multiply it by 15 MB. Most users will keep less than 2000 pictures per year which requires less than 30 GB/year. Assuming that you will change your hard disk (or whatever media in the future) every 4-5 years, the natural increase in storage capacity will suffice to keep you afloat.

The more ambitious ones out there will need more space, much more maybe. Think of buying a file server, Giga-Ethernet comes integrated into motherboards today and it's a flick to fetch the files over the local network. Speaking about modern mobos: they now have external SATA connectors. This makes it really a trifle to buy an external SATA drive and hook it up to your machine. 1000 GB drives will hit the market this year (2008). These are terrific compact storage containers for backup swapping: keep one drive at home and one somewhere else.

##### Back it up, backup, backup, recover!

A 750GB HD costs €100 today. Do not blame anybody else for data loss! 6% of all PCs will suffer an episode of data loss in any given year. Backup your data often according to a plan, and back it up and test the backup before you do anything dramatic like re-installing your OS, changing disks, resizing partitions and so on.

###### Disaster prevention

Say, you religiously do your backups every day on a external SATA drive. Then comes the day where lightning strikes. Happy you if the external drive was not connected at that moment!

Disasters strike locally and destroy a lot. Forget about airplane crashes: fire, water, electricity, kids and theft are dangerous enough to our data. They usually cover a whole room or house.

Therefore disaster control means de-localized storage. Move your backups upstairs, next house, to your bureau (and vise versa), whatever.

There is another good aspect to the physical separation: as said above, panic is often the cause of destroying data, even the backup data. Having a backup not at hand right away may safe your ass one day.

###### Some backup technicalities explained for laymen.

- Full Backup: A complete backup of all the files being backed up. It is a snapshot without history, it represents a full copy at one point in time.

- Differential Backup: A backup of only the files that have changed since the last full backup. Constitutes a full snapshot of two points in time: the full backup and the last differential one.

- Incremental Backup: A backup of only the files that have changed since last whatever backup. Constitutes multiple snapshots. You can recreate the original state at any point in time such a backup was made. This comes closest to a versioning system except that it is only sampled and not continuous.

###### Best practice: The IT-layman's backup cookbook

1. do a full backup in a external storage device.

2. verify its data integrity and put it away (disaster control)

3. have another storage device for frequent backups

4. swap the devices every other month after having verified data integrity

###### A useful rsync recipe to backups

Rsync is a wonderful little utility that's amazingly easy to set up on your machines. Rather than have a scripted FTP session, or some other form of file transfer script - rsync copies only the differences of files that have actually changed, compressed and through ssh if you want to for security. That's a mouthful.

A reasonable backup approach for images could be this one:

1. backup important images right away (after dumping them to a computer) to DVD/optical media

2. do daily incremental backup of the work space

3. do a weekly differential backup and delete integral backups of week-2 (two weeks ago)

4. do a monthly differential backup and delete backup of month-2

5. if not physically separated already, separate it now (swapping-in another backup drive)

This protocol tries to leave you enough time to spot losses and to recover fully at the same time keeping the backup volume at <130% of the working space. You end up with a daily version of the last 7-14 days, a weekly snapshot for at least one month, and a snapshot of every month. Any more thinning should be done by hand after a full verification.

For German speaking *nix users: link

##### Preserve your images through the changes of technology and owners

Themes: metadata, IPTC stored in image files, XMP files associated, keep the originals, storage, scalability, media, retrieval of images and metadata, copying image data over to the next generation of media, applications, operating systems, virtualization, viewing device... use of the www.

In order for your valuable images to survive the next 40 years or so (because that's about the time that you will become really interested to revisit those nice old photographs of you as a child, adolescent &etc;) there are two strategies to be observed:

1. Keep up with technology, don't lag behind more than a couple of years.

2. Save your photos in an open, non-proprietary standard.

###### How to keep up with technology?

As the future is unforeseeable by nature, everything said today is to be taken with caution, and to be reviewed as we advance. Unfortunately there is no shortcut possible to some basic vigilance. Every 5-8 years at least one should ask oneself the question of backwards compatibility of current systems. The less variants we used in the past the less questions are to be answered in the future.

Of course every time you change your computer system (machine, operating system, applications, DRM) you have to ask yourself the same questions. Today, if you want to switch to Windows Vista, you have to ask yourself three times if you still can import your pictures, and, more important so, if you are ever able to move them onto some other system or machine. Chances are good that you cannot. I see many people struggling around me, because Vista enforces a strict DRM regime. How can you proof to Vista that you are actually the owner of your pictures copyright?

Basically the questions should be answered along the line explained in this document: use and change to open standards supported by a manifold of applications.

Virtualization becomes available now for everybody. So if you have an old system that is important for reading your images, keep it, install it as a virtual machine for later.

Otherwise the advice is quite simple: every time you change your computer architecture, your storage and backup technology, your file format, check it out, go through your library and convert to a newer standard if necessary. And keep to open standards.

###### Scalability

Scalability is the tech-geek expression of the (easy) capability of a system to be resized, which always means up-sized.

EMVS /LVM Todo

Lets assume you planned for scalability and dedicated the container you want to increase to a separate disk or partition. On *nix systems like &Linux; you then can copy and resize the container to the new disk:

Check with dmesg if your new disk is recognized by the system, but don't mount it.

>     $ dd if=/dev/sdb[#] of=/dev/sdc # source is /dev/sdb, new disk is /dev/sdc
>     $ parted resize /dev/sdc1 0 <disk size in MB> # works on ext2,3, fat16, 32 and reiserfs
>     $ resize2fs /dev/sadc1  #resize_reiserfs in case

Todo

###### Use open, non-proprietary standards as file formats

The short history of the digital era in the past 20 years has proven over and over again that proprietary formats are not the way to go when you want your data to be intelligible 10 years into the future. Microsoft is certainly the well known culprit of that sort because of its domineering market share. But other companies are actually (if inadvertently) worse since they may not stay long enough in the market at all or have a small user/contributor base only. In the case of Microsoft one has at least the advantage of many people sharing the same problems. Finding a solution has therefore much more success. Still, in some cases Microsoft is using Open Source documentation to understand their own systems, so badly maintained have been their own documentation. Usually with any given MSoffice suite one cannot properly read a document created with the same application two major versions earlier.

Image formats have had a longer live time than office documents and are a bit less affected by obsolescence.

Open Source standards have the huge advantage of having an open specification. Even if one day in the future there'll be no software to read it anymore, one can recreate such software, a task becoming simpler every year.

`JPEG` has been around for a while now, and whilst it's a lossy format losing a bit every time you make a modification and save it, it is ubiquitous, supports JFIF, EXIF, IPTC and XMP metadata, has good compression ratios and can be read by all imaging software. Because of its metadata limitation, lossy nature, absence of transparency and 8 bit color channel depth, we do not recommend it. JPEG2000 is better, can be employed lossless, but lacks in user base.

`GIF` is a proprietary. patented format and slowly disappearing from the market. Don't use it.

`PNG` has been invented as a Open Source standard to replace GIF, but it does much more. It is lossless, supports XMP, EXIF and IPTC metadata, 16 bit color encoding and full transparency. PNG can store gamma and chromaticity data for improved color matching on heterogeneous platforms. Its drawback are a relatively big footprints (but smaller than TIFF) and slow compression. We recommend it.

`TIFF` has been widely accepted as an image format. TIFF can exist in uncompressed form or in a container using a lossless compression algorithm (Deflate). It maintains high image quality but at the expense of much larger file sizes. Some cameras let you save your images in this format. The problem is that the format has been altered by so many people that there are now 50 or more flavors and not all are recognizable by all applications.

`PGF` "Progressive Graphics File" is another not so known but open file image format. Wavelet-based, it allows lossless and lossy data compression. PGF compares well with JPEG 2000 but it was developed for speed (compression/decompression) rather than to be the best at compression ratio. At the same file size a PGF file looks significantly better than a JPEG one, while remaining very good at progressive display too. Thus it should be well-suited to the web but at the moment few browsers can display it. For more information about the PGF format see the libPGF homepage.

`RAW` format. Some, typically more expensive, cameras support RAW format shooting. The RAW format is not really an image standard at all, it is a container format which is different for every brand and camera model. RAW format images contain minimally processed data from the image sensor of a digital camera or image scanner. Raw image files are sometimes called digital negatives, as they fulfill the same role as film negatives in traditional chemical photography: that is, the negative is not directly usable as an image, but has all of the information needed to create an image. Storing photographs in a camera's RAW format provides for higher dynamic range and allows you to alter settings, such as white balance, after the photograph has been taken. Most professional photographers use RAW format, because it offers them maximum flexibility. The downside is that RAW image files can be very large indeed.

My recommendation is clearly to `abstain from archiving in RAW format` (as opposed to shooting in RAW format, which I recommend). It has all bad ingredients: many varieties and proprietary nature. It is clear that in a few years time you cannot use your old RAW files anymore. I have already seen people changing camera, losing their color profiles and having great difficulty to treat their old RAW files correctly. Better change to DNG format!

`DNG` Digital Negative file format is a royalty free and open RAW image format designed by Adobe Systems. DNG was a response to demand for a unifying camera raw file format. It is based on the TIFF/EP format, and mandates use of metadata. A handful of camera manufacturers have adopted DNG already, let's hope that the main contenders Canon and Nikon will use it one day.

I strongly recommend converting RAW files to DNG for archiving. Despite the fact that DNG was created by Adobe, it is an open standard and widely embraced by the Open Source community (which is usually a good indicator of perennial properties). Some manufacturers have already adopted DNG as RAW format. And last not least, Adobe is the most important source of graphical software today, and they of course support their own invention. It is an ideal archival format, the raw sensor data will be preserved as such in TIFF format inside DNG, so that the risk associated with proprietary RAW formats is alleviated. All of this makes migration to another operating system a no-brainer. In the near future we'll see 'non-destructive editing', where files are not changed anymore but rather all editing steps will be recorded (into the DNG as it were). When you open such a file again, the editing script will be replayed. This takes computation power, but it is promising as it leaves the original intact and computing power increases all the time.

`XML` (Extensible Mark-up Language) or `RDF` (Resource Description Framework). XML is like HTML, but where HTML is mostly concerned with the presentation of data, XML is concerned with the "representation" of data. On top of that, XML is non-proprietary, operating-system-independent, fairly simple to interpret, text-based and cheap. RDF is the WC3's solution to integrate a variety of different applications such as library catalogs, world-wide directories, news feeds, software, as well as collections of music, images, and events using XML as an interchange syntax. Together the specifications provide a method that uses a lightweight ontology based on the Dublin Core which also supports the "Semantic Web" (easy exchange of knowledge on the Web).

IPTC goes XMP

That's probably one of the reasons why, around 2001, that Adobe introduced its XML based XMP technology to replace the "Image resource block" technology of the nineties. XMP stands for "Extensible Metadata Platform", a mixture of XML and RDF. It is a labeling technology that lets users embed data about a file in the file itself, the file info is saved using the extension".xmp" (signifying the use of XML/RDF).

`XMP`. As much as ODF will be readable forever (since its containing text is written in clear text), XMP will preserve your metadata in a clearly understandable format XML. No danger here of not being able to read it later. It can be embedded into the image files or as a separate accompanying file (sidecar concept). XMP can be used in PDF, JPEG, JPEG2000, GIF, PNG, HTML, TIFF, Adobe Illustrator, PSD, PostScript, and Encapsulated PostScript. In a typical edited JPEG file, XMP information is typically included alongside Exif and IPTC data.

Embedding metadata in files allows easy sharing and transfer of files across products, vendors, platforms, customers, without metadata getting lost. The most common metadata tags recorded in XMP data are those from the Dublin Core Metadata Initiative, which include things like title, description, creator, and so on. The standard is designed to be extensible, allowing users to add their own custom types of metadata into the XMP data. XMP generally does not allow binary data types to be embedded. This means that any binary data one wants to carry in XMP, such as thumbnail images, must be encoded in some XML-friendly format, such as Base64.

Many photographers prefer keeping an original of their shots (mostly RAW) for the archive. XMP suits that approach as it keeps metadata separate from the image file. I do not share this point of view. There could be problems linking metadata file and image file, and as said above, RAW formats will become obsolete. I recommend using DNG as a container and putting everything inside.

The Dublin Core Metadata Initiative is an open organization engaged in the development of interoperable online metadata standards that support a broad range of purposes and business models. DCMI's activities include work on architecture and modeling, discussions and collaborative work in DCMI Communities and DCMI Task Groups, annual conferences and workshops, standards liaison, and educational efforts to promote widespread acceptance of metadata standards and practices.

##### Best practice: Data protection

- Use surge protectors (UL 1449 standard), possibly combined with a UPS

- use ECC memory to verify correct data transmission (even just saving files)

- watch your hard drives (temperature, noise...), make backups

- Keep backups at another location, locked up, use web storage space

- use archival media and burners

- Don't panic in case of data loss, explain your recovery plan to a layperson

- choose you file system, partitions, folders to cater for easy scalability

- Use open, non-proprietary standards to manage and save photographs

- Do a technology/migration review at least every 5 years

#### A typical DAM workflow with &digikam;

1. import images from camera, card reader or scanner. As long as the images are stored on the camera media, you can use that as temporary backup.

2. RAW are converted to DNG and stored away into an RAW archive (not yet implemented)

3. rate and cull, write-back metadata to the DNG archive

4. make a backup ⪚ on DVD, optical drive or tape

5. tag, comment, geo-locate

6. edit and improve photographs

7. For layered editing use external applications. Back in &digikam;, re-apply the metadata, which was probably lost or curtailed by the other applications.

8. run the routine backup with following data-integrity checks

9. protect processed images for copyrights with Digital Watermarking. Export to web galleries, slide shows, MPEG encode, contact sheets, printing &etc;

Workflow

### Using a Digital Camera With &digikam;

#### Introduction to Camera Interface

The Camera Tool allows you to download your photographs directly from your camera into a &digikam; Album. You can access the Camera Tool by clicking on the Camera menu and selecting from the list of configured cameras. See the Setup Camera Section of the manual for instructions on how to setup &digikam; to work with your camera. If you want to have more information about how &digikam; supports digital cameras, please a take a look at this section.

The Camera Interface is not the only way to get your photographs into &digikam;. See the Adding a photograph to an Album section for a description of how to add photographs that are already on your hard disk. But Camera Interface provides a lots of advanced settings to import images into your albums database.

To be able to use your digital camera with &digikam;, connect the camera to your computer, switch the camera to the image display mode and turn it on. See you camera's user manual if you need more information.

When you start the Camera Interface, it will try to connect to the Camera. For some cameras this connection phase can take a little while. When connected, a Ready indicator will appear on the bottom and thumbnails of any photographs on the camera will be displayed. Some cameras cannot provide thumbnails of the photographs. If this is the case, you will only see the filenames and a mime-type icon for each item stored by your camera (photograph, movies, sounds, etc).

##### The Camera Client Window

The Camera Client Window

#### Getting information about photographs from the Camera

Before downloading photographs to your computer, you may wish to see camera item information. Using the Properties and Metadata side bar tabs from Camera Interface will launch camera item properties and metadata information.

##### The Camera Item Properties Sidebar Tab

The camera item properties sidebar Tab

The Properties tab displays file information recorded by the camera and a resume of photographer information to describe how the image has been taken. A flag indicates if the image has not yet been downloaded to the computer. Note, all this information may be unavailable with some digital cameras.

The Metadata tab displays an internal picture's metadata like EXIF, Makernotes, GPS, &etc; This information is the same as sidebar Meta-Data from the &digikam; main interface or image editor. Note, all these metadata can be unavailable with some digital cameras.

#### Downloading photographs to your computer

The simplest way to download photographs from your camera to your computer is to click the Download button and then click Download All. This will download all of the photographs on the camera to a single Album in &digikam;. The download process will not remove the photographs from the camera. It is always advisable to check that the photographs have downloaded safely into the Album you were expecting before deleting them from the camera.

If you do not want to download all of the photographs you can select just those that you need using the standard &kde; selection methods. Once you have the photographs selected, click Download and then Download Selected. The Download Selected button will be grayed out until you have selected some photographs.

If supported by your camera an option Download new is available. Those are images not yet downloaded by &digikam;. In that case the new images are already marked with a star in the thumbnail window. Obviously if you choose this handy option, it will download the new images only.

#### Selecting a Target Album

Using Download All or Download Selected buttons will bring up a dialog, that allows you to select a target Album into which the photographs will be downloaded. The list of existing Albums is displayed, ordered by the Folder method (see the Albums View for details of Album ordering). You can select the target Album from this list and then click OK.

##### The Target Album Selection Dialog

The Target Album Selection Dialog

If you want to create a new Album, into which you could download the photographs, click the New Album button. The new Album will be created as a sub-folder of the Album that is currently selected in the existing Album list. This means that, if you do not want your new Album to be a sub-folder of an existing folder, you must first select the "My Albums" entry from the very top of the existing Albums list before creating a new Album.

When you have selected the target Album, click OK and &digikam; will download the photographs from the camera to that album.

The Downloading in Progress

#### Deleting photographs from the camera

Once you are happy with the downloaded photographs that you wanted, you are ready to delete photographs from the Camera. You can delete all of the photographs at once by clicking the Delete Delete All button. If you just want to delete a selection of the photographs, you have to select those that you want to delete and click Delete Delete Selected

Please note that there is no way to restore a photo that you have deleted from the camera. The photographs are not moved to the &kde; Trash Can, they are removed completely. It is best to double check that you have successfully downloaded a photograph into a &digikam; Album before you delete it from the camera. Anyway, if you plan to empty the camera card, you better do that from the camera menu because it is much quicker.

#### Automatic Renaming

Cameras often do not use very meaningful filenames for photographs. The filenames are usually reused once the photographs have been deleted from the camera. This can lead to filename clashes if you download photographs from many shootings into the same Album. It can also be useful to include the date and time that an image was taken into the filename.

##### Files Renaming Options

Files Renaming Options

&digikam; can automatically rename your photographs using the date and time information included by the camera in the photograph. To use this feature, click the Settings button on the Camera Interface. The Camera Interface window will expand to reveal some extra features. Select Customize and then enter any filename prefix you would like. As an option you can add many information independently or by combination including : date, time, original file name, file extension, directory, owner, group, camera name, a sequence number or any other metadata from the photograph.

In the next box you find the options for rotating/flipping the image and for date based subalbums. If you check the latter option, folder per day will be automatically generated.

The 'On the fly operations' open three more options that act on the photos before storing them on disk. The first two relate to the authors data in Default Author Identity settings. If checked, the respective items will be copied into the EXIF tags and IPTC fields. The last option allows a date & time for all downloaded photographs to be set.

- The sequence number may be needed if you have a camera with a very fast multi-shoot mode where it is possible to get two photographs with exactly the same data and time.

- If you want another date format then the default date format, click on Date & Time..., choose Custom in Format drop-down list and fill in for example "dd.MM.yyyy hh:mm:ss". For more information, read QdateTime class reference.

- When you select Camera filenames, you have the option to change the filenames to lowercase when downloading. Or use uppercase if you prefer.

The new filename that &digikam; will use for the photographs when they are downloaded is shown underneath the name provided by the camera in the thumbnail view. The renaming settings will be remembered the next time you use the camera interface.

#### Camera Information Based Operations

##### Automatic Rotation

&digikam; can use any information about the orientation of the camera at the moment the photograph was taken for automatic rotation of the photograph when it is downloaded. Not all cameras include this information. See the sidebar Meta-Data section for more detail about information that your camera may have embedded in your photographs.

###### On the fly Operations Options

On the fly Operations Options

This automatic rotation is switched on by default, and if your camera does not include the information, &digikam; will leave the photograph at its original orientation. If you would like to switch the automatic rotation off, click the Advanced button and deselect the Auto Orient option at the bottom of the window.

##### Automatic Destination Albums Creation

If your camera provides information about the date of the photograph's taking, &digikam; can use this to automatically create subalbums in the destination Album when it is downloaded. Subalbums names will be based on image dates. All images which have the same date will be downloaded into the same subalbum. Not all cameras include this information. See the sidebar Meta-Data section for more detail about information your camera may have embedded in your photographs.

###### Albums Auto-creation Options

Albums Auto-creation Options

This option is switched off by default and in this case &digikam; will download the photographs in the root destination Albums. If you would like to switch on this option click the Advanced button and select the Download photo in automatically option at the bottom of the window.

#### Uploading Photographs to your camera

The simplest way to upload photographs from your computer to your camera is to click the Download button and then click Upload. A standard &kde; file selection dialog will appear to select the files from your computer to copying on your camera. You can select more than one file using the standard &kde; selection methods.

When images selection is done, &digikam; will ask you where you want to upload the files on your camera. A camera folder selection dialog will appear. Just select one folder and press OK to start uploading. No images will be removed from your computer.

##### The Camera Folder Selection Dialog

The Camera Folder Selection Dialog

Uploading feature is not supported by all camera drivers.

#### How to use a GPS device with &digikam;

GPS (global positioning system) is used as a generic term throughout this document. It just means a location in latitude and longitude global coordinates that can be displayed on a map. The actual technical implementation that provides the data can be the American GPS, the Russian GLONAS, the European GALILEO or any other system.

Not only for professional photographers can it be interesting to link an image to a precise geographical location. Not everybody uses an airplane to overfly and scan a certain area with automatic GPS data recording. Environmental planners, military, police, construction bureaus, real estate agencies, all will have an immediate application.

But if, after some time, one has forgotten where the image was taken, if one loves the nice feature to open with a simple click a browser displaying a zoom of the area, if you like to send your image as a postcard to another &digikam; user (who is then able to locate your shot), or if you simply need the documentation aspect of it - having position data stored in a photo is great.

Now, how do we get GPS data into the images? exiv2 supports many kinds of the GPS data fields, even bearing, satellite and map references. So the question is really how to get the data into those fields? There are at least three ways to do this: directly with the appropriate hardware, per post-treatment of GPS and image files using the Geolocation Kipi-plugin (Manual) and per 'manual' insertion of known locations.

- Direct GPS data insertion into the image files

  To our knowledge there is at the time of writing no camera that integrates a GPS unit. But there are a few that combine with GPS receivers, either as a plug-in card or by data transmission through cable or Bluetooth.

  Selfmade Howto

- Post-treatment of GPS data and image files

  Using the Geolocation Kipi-plugin (Manual if Kipi-plugins are already installed).

  This approach is dead easy: while taking your pictures just keep a GPS device running and carry it around with the camera. Once you are done, download the pictures and the GPS tracks, and run the above plugin. It will correlate the data in the time domain; so it is important that the camera be accurate in its clock setting (the GPS device is always accurate through the satellites). The positional accuracy interpolated from the track points can be as good as 20 meters. Of course, this approach only works if your camera can record EXIF data.

  The GPS track download from a device can be managed with the gpsman or gpsbabel. It is important that the downloaded tracks are being stored in gpx format, which is the only one compatible with the Geolocation plugin.

  Several programs exist for &Windows; and MacOS that are able to extract and correlate data from images and GPS data tracks. The following site provides the same functionality for &Linux;: gpsCorr or gpsPhoto

- 'Manual' insertion of known locations

  If you happen to know the latitude/longitude or other data you can use the this script which is a GPS wrapper for Phil Harvey's ExifTool that uses the signed floating number coordinate notation as produced by maps.google.

GPS devices: GPS tracker from Sony and EMTAC bluetooth GPS

### &digikam; Configuration

#### The Setup Section

&digikam; tries to give you as much control over how it works as possible. There are many options that change the behavior of &digikam;. To access these settings select Settings Configure &digikam; from the menubar. The configuration dialog is separated into 15 pages. You can change between these pages by clicking on the icons on the left-hand side of the dialog.

- Album Settings

- Collection Settings

- Default Author Identity

- Metadata (embedded information)

- Tooltip Settings

- Mime Type Settings

- Light Table Settings

- Image Editor Settings

- Save Image Options

- RAW Decoder Settings

- ICC Profiles setup

- Kipi Plugins Settings

- Slide show settings

- Camera Interface Settings

- Miscellaneous Settings

##### Album Settings

The Album settings control how the main application will behave.

The Album Library Path is the location on your hard disk where &digikam; will store all of the Albums. If you change this location without manually moving all of the Albums on the hard disk, &digikam; assumes that there are no existing Albums and will generate a new database at the new location. Your old Albums will not be altered but you will need to change the Album Library Path back to the old location to access them. If you are not sure of what you are doing it is best not to change this location.

The Thumbnails options are described in the Images section.

The Click action can be set to Show embedded preview or Start image editor. You herewith define the default behavior of &digikam; when you click on an image item in the main view.

##### Collection Settings

This dialog manages your Collection types. Album Collections are described in detail in the Albums section.

##### Default Author Identity for IPTC

This page contains the default identity and copyright data as shown on the printscreen below. The data will be automatically written into the respective IPTC data fields if so selected during the download from the camera interface. Also, if you call for database synchronisation, this data will be written into the IPTC fields.

This is an extract of the IPTC specifications:

- Author (is synonymous to Creator and By-line): This field should contain your name, or the name of the person who created the photograph. If it is not appropriate to add the name of the photographer (for example, if the identity of the photographer needs to be protected) the name of a company or organization can also be used. Once saved, this field should not be changed by anyone. This field does not support the use of commas or semi-colons as separator.

- Author title (synonymous with By-line title): This field should contain the job title of the photographer. Examples might include titles such as: Staff Photographer, Freelance Photographer, or Independent Commercial Photographer. Since this is a qualifier for the Author field, the Author field must also be filled out.

- Credit (synonymous with Provider): Use the credit field to identify who is providing the photograph. This does not necessarily have to be the author. If a photographer is working for a news agency such as Reuters or the Associated Press, these organizations could be listed here as they are "providing" the image for use by others. If the image is a stock photograph, then the group (agency) involved in supplying the image should be listed here.

- Source: The Source field should be used to identify the original owner or copyright holder of the photograph. The value of this field should never be changed after the information is entered following the image's creation. While not yet enforced by the custom panels, you should consider this to be a "write-once" field. The source could be an individual, an agency, or a member of an agency. To aid in later searches, it is suggested to separate any slashes "/" with a blank space. Use the form "photographer / agency" rather than "photographer/agency." Source may also be different from Creator and from the names listed in the Copyright Notice.

- Copyright Notice: The Copyright Notice should contain any necessary copyright notice for claiming the intellectual property, and should identify the current owner(s) of the copyright for the photograph. Usually, this would be the photographer, but if the image was done by an employee or as work-for-hire, then the agency or company should be listed. Use the form appropriate to your country. For the United States you would typically follow the form of © {date of first publication} name of copyright owner, as in "©2005 John Doe." Note, the word "copyright" or the abbreviation "copr" may be used in place of the © symbol. In some foreign countries only the copyright symbol is recognized and the abbreviation does not work. Furthermore the copyright symbol must be a full circle with a "c" inside; using something like (c) where the parentheses form a partial circle is not sufficient. For additional protection worldwide, use of the phrase, "all rights reserved" following the notice above is encouraged. In Europe you would use: Copyright {Year} {Copyright owner}, all rights reserved. In Japan, for maximum protection, the following three items should appear in the copyright field of the IPTC Core: (a) the word, Copyright; (b) year of the first publication; and (c) name of the author. You may also wish to include the phrase "all rights reserved."

##### Metadata (embedded information settings)

Image files can have some meta-data embedded into the image file format. This meta-data can be stored in a number of standard formats. &digikam; can read meta-data in the EXIF format if it is present in the file. &digikam; can also write captions into the EXIF information. Writing captions to the EXIF section is limited to JPEG images for now (the exiv2 library is in development and will be extended to PNG and TIFF format metadata embedding in the near future).

These settings allow you to control how &digikam; will deal with this embedded information.

Show images/thumbnails rotated according to orientation tag : this will use any orientation information that your camera has included in the EXIF information to automatically rotate your photographs so that they are the correct way up when displayed. It will not actually rotate the image file, only the display of the image on the screen. If you want to permanently rotate the image on file, you can right-click on the thumbnail and select Auto-rotate/flip according to EXIF orientation. The image will then be rotated on disk and the tag will be reset to "normal". If your camera routinely gets this orientation information wrong you might like to switch this feature off.

Set orientation tag to normal after rotate/flip : the Auto Rotate option automatically corrects the orientation of images taken with digital cameras that have an orientation sensor. The camera adds an orientation tag to the image's EXIF meta-data. &digikam; can read this tag to adjust the image accordingly. If you manually rotate an image, this meta-data will be incorrect. This option will set the orientation tag to "Normal" after an adjustment, assuming that you rotated it to the correct orientation. Switch this off if you don't want &digikam; to make changes to the orientation tag, when you rotate or flip the image.

The IPTC Actions will save the data into the respective IPTC fields, which ensures a permanent metadata storage in the image and not only in &digikam;'s database. Thus, metadata is persistent across applications, and may be exported or imported into &digikam; without loss.

Save image captions as embedded text : this will synchronize the captions that you add to your photographs with those in embedded in the image. This is useful because the captions embedded in the image can be read by other image viewers. Care should be taken if you have images that already have captions embedded in them because these captions will be overwritten by the captions made within &digikam;.

##### Tooltip Settings

This setup page covers all options of information appearing when the mouse hovers over a file in the main view. According the checked options they will be shown or not.

##### Mime Type Settings

&digikam; can understand lots of different image file types as well as some video and audio formats. To control which types of files &digikam; will try to display you can add or remove file extensions from these lists. Any files that are in the &digikam; Album folders that do not match these extensions will be ignored by &digikam;.

The default settings can be easily restored by clicking on the update buttons to the right of each category.

##### Light Table Settings

The setting of the &digikam; Light Table can be set to default values on this page so that every time you open the Light Table, these settings are activated (if possible, because for images having different sizes the synchronous mode does not work). The "Load full image size" is only recommended for fast maschines, but if you have one, enable this option for better viewing results.

##### Image Editor Settings

By default the Image Editor will use a black background behind photographs when they are displayed. If you prefer a different background color you can choose one here. You can also turn off the ToolBar when the Image Editor is in full screen mode.

Over and underexposed areas of an image can be indicated by dark and light marker colors that can be defined here. In the editor this viewing mode can be switched on and off with F10 and F11 respectively.

##### Save Image Options

When changes are made to JPEG files and they are saved back to the hard disk the JPEG file must be re-encoded. Each time a JPEG file is encoded a decision must be made on the level of quality that is to be applied. Unfortunately the level of quality applied is not recorded in the image file. This means that the Image Editor cannot use the same quality ratio when saving an altered image as was used for the original image. You can change the default level of quality that the Image Editor will apply when it saves altered images by moving the JPEG quality slider (1: low quality / 100: high quality and no compression).

Chroma subsampling is the practice of encoding images by implementing more resolution for luminance information than for color information. Please read this Wikipedia article for a full explanation.

With PNG compression option, you can reduce PNG image files size. This operation does not reduce image quality because PNG uses a lossless algorithm. The only effect is that image data needs more time to compress/decompress. If you have a fast computer you can change this value to use a high compression factor (1: low compression / 9: high compression).

With Compress TIFF option, you can toggle to use Deflate compression algorithm with TIFF image files. This will reduce TIFF image files sizes. It has no image quality effect because Deflate is a lossless algorithm.

With the LossLess JPEG 2000 files option allows for lossless storage, or, if the lossy options is selected, even then the quality for comparative files size is much better than normal JPEG. At the time of writing, metadata is not yet supported, but it is in the 'pipeline'.

##### RAW Decoder Settings

In the early versions of &digikam; the Image Editor was just a viewer for photographs, but it is rapidly developing into a very useful photo manipulation tool. This dialog allows you to control how the Image Editor will behave.

16-bit color depth

If enabled, all RAW files will be decoded to 16-bit color depth using a linear gamma curve. To prevent dark image rendering in the editor, it is recommended to use Color Management in this mode. If disabled, all RAW files will be decoded to 8-bit color depth with a BT.709 gamma curve and a 99th-percentile white point. This mode is faster than 16-bit decoding. In 8-bit mode only will the brightness setting be taken into account (dcraw limitation).

Interpolate RGB as four colors

The default is to assume that all green pixels are the same. If even-row green pixels of the CCD sensor are more sensitive to ultraviolet light than odd-row this difference causes a mesh pattern in the output; using this option solves this problem with minimal loss of detail. To resume, this option blurs the image a little, but it eliminates false 2x2 mesh patterns with VNG quality method or mazes with AHD quality method.

Use camera white balance

Use the camera's custom white-balance settings if set. Otherwise apply Automatic color balance if this option is set.

Automatic color balance

Only used if camera white balance is not set. The default is to use a fixed color balance based on a white card photographed in sunlight.

Use Super CCD secondary sensors

For Fuji Super CCD SLR cameras only. Use the secondary sensors, in effect underexposing the image by four stops to reveal detail in the highlights. For all other camera types this option is being ignored.

Highlights

This is the story of the three highlight options, courtesy of Nicolas Vilars:

Default is here to consider highlights (read: part of your images that are burned due to the inability of your camera to capture the highlights) as plain / solid white (solid white option). You can get some fancy results with the unclip option which will paint the highlights in various pinks. At last you can try to consider recovering some parts of the missing information from the highlights (reconstruct option).

This is possible because the blue pixels tends to saturate less quickly than the greens and the reds. &digikam;/dcraw will try to reconstruct the missing green and red colors from the remaining none saturated blue pixels. Of course here everything is a question of tradeoff between how much color or white you want.

If you select reconstruct as the option, you will be given the choice to set a level. A value of 3 is a compromise and can/should be adapted on a per image basis.

A small warning here, for the few curious that have read the man pages of Dcraw, the author says that 5 is the compromise, 0 is solid white and 1 unclip. This is because in &digikam; 0 and 1 are the "solid white" and "unclip" options in the drop down menu (if you select these, the level slider will be grayed out). Therefore, the slider in &digikam; with the "reconstruct" option will let you choose between 0 to 7 (instead of 0 to 9 in Dcraw command line) where 3 is the compromise instead of 5 in "native" Dcraw command line tool.

Brightness (works in 8 bit mode only)

Set the luminosity to your taste, you probably need to go a little higher than the default = 1. But this can be adjusted later with the image options in the &digikam; image editor. Given the cost in time for demosaicing, stay conservative.

Quality

A demosaicing algorithm is a digital image process used to interpolate a complete image from the partial raw data received from the color-filtered image sensor internal to many digital cameras in form of a matrix of colored pixels. Also known as CFA interpolation or color reconstruction.

&digikam; and Dcraw offer us three alternatives: bi-linear, VNG interpolation, AHD interpolation. It seems that AHD interpolation (for Adaptive Homogeneity-Directed) is the best choice for quality according to some test that I have performed and the paper of the person that implemented it. VNG interpolation (Variable Number of Gradients) was the first algorithm used by Dcraw but suffers from color artifacts on the edge. Bilinear is interesting if you are looking for speed with a acceptable result.

Enable Noise Reduction

While demosaicing your image you can additionally ask for noise reduction (at a slight speed penalty). This option applies a noise reduction algorithm while the image still is in CIE Lab color space. Because the noise is only applied to the Luminosity layer (the "L" of the Lab), it should not blur your image as traditional noise reduction algorithms do in RGB mode. So, if you converted an image from RAW and it appears noisy, rather than applying a denoiser, go back and re-convert with this option enabled. The defaults are: Threshold = 100. Higher values will increase the smoothing, lower will decrease smoothing.

Enable chromatic aberration (CA) correction

If you know the CA of your lenses you can set the red and blue correction values here. This is certainly the optimal method for CA correction as it is done during RAW conversion.

##### ICC Profiles setup

&digikam; is color-management enabled. RAW files - as they come - are not color managed at all. Your camera provides the data it has captured in a raw format and will let you manage all the processing. Every camera has its specifics as to how it captures color information, therefore you will need to apply a specific profile to the images you want to process. Please refer to the section ICC color profile management for more details an explanations.

Basically, a profile "maps" the color information and gives information on how one should render them. It gives also information to LCMS and &digikam; on how to translate the color information from one color space to an other in order to keep the colors as accurate as possible across all rendring media.

Behavior Ask when opening an image in image editor / Launch Color Management tool with RAW files

Color Profiles Directory Set this to the folder where you store all your profiles ⪚ "/usr/share/color/icc" or "/home/user/.color/icc". &digikam; will scan this folder when starting up.

ICC Profiles Settings Here you are given the ability to provide "default" choices for your profiles. Everything is adaptable later-on at the opening of a RAW file.

- The Use color managed view is an alternative to using Xcalib or Argyll. Only your image will be color managed, not your entire screen!

- You have to provide a workspace profile (linear profiles such as sRGB, ECI-RGB, LStar-RGB, Adobe-RGB or CIE-RGB). If you want to print your images, you may want to opt for Adobe RGB, if it is only for web publishing, sRGB is better (Adobe RGB will be displayed slightly dull in non color managed enabled software such as browsers). However you may change this later of course (by attributing another profile), therefore Adobe RGB can be a good choice for storing and image handling as you can always change it to sRGB before releasing an image for your blog.

  Do not use non-linear profiles as they will change the color-balance

- The input profile should match the camera maker and model you are using. 'Not all profiles are created equal', there are some that have no tone mapping/gamma correction included (Canon). As of now, dcraw does not correct gamma for 16 bit depth conversion, which means that you have to do the tone mapping yourself.

- There are some other options such as the soft proof profile which enables you to emulate, granted that you have a profile for it, how your image will render for a particular device. It is useful before printing for instance because your printer has a smaller gamut than your camera and some colors might look saturated. You may want to fix this manually instead of relying on the "blind" algorithm of your printer.

For most cameras it is pretty obvious what color profile they propose for the type at hand, not so for the Canon's. Here is a table of camera/profiles matches, it is non-authoritative of course:

Camera | Profile series
Canon 1D mark II | 6051
Canon 1D mark II | 6111
Canon 1Ds | 6021
Canon 1Ds mark II | 6081
Canon 5D | 6091
Canon 10D | 6031
Canon 20D | 6061
Canon 30D | 6112
Canon 40D | 6101
Canon 300D | 6031
Canon 350D | 6111 or 6071
Canon 400D | 6131

The Canon profile extension betray the target style: F for Faithful Style, L for Landscape Style, N for Neutral Style, P for Portrait Style, S for Standard Style.

Here you find a typical RAW workflow scenario.

##### Kipi Plugins Settings

Kipi is the &kde; Image Plugin Interface. It is an interface that is supported by a number of &kde; image viewer/editor applications. By providing this interface, &digikam; can take advantage of many plugins that are written to work with any application that implements the Kipi interface.

If your operating system has the Kipi plugins package installed, you will see a list of available plugins. Select those that you want to use and they will be loaded into &digikam;. The plugins will appear as new menu entries in the main menu bar and in the context menu for thumbnails.

Keyboard shortcuts to actions that plugins perform can be set up in the Setting Configure Shortcuts menu.

For more information about Kipi plugins, you can consult the Kipi-plugins manual.

##### Slide show setup

The slide show setup should be easy to understand. The upper slider adjusts the time between image transitions; usually a time of 4-5 seconds is good. The other check boxes enable/disable the metadata to be shown on the bottom of the slide show images during display.

##### Camera Interface Settings

The camera settings shows on the left of the list of the currently supported cameras. On the right at the top there is an auto-detect button, which tries to identify the camera connected to your computer (make sure that the camera is connected properly to the computer and turned on in the image display mode). Below this are the port settings; the currently supported are Serial, USB, and USB/FireWire Mass Storage.

Clicking on a camera in the list on the left will display the supported ports which you can then select. If there is only one supported port it will be automatically selected. At the bottom on the right there is a box for setting the exact path in case of a serial port. Please note that USB interface does not need any paths to be set. If you cannot find your camera on the list, you can try to use a generic Mass Storage device selecting Mounted Camera item in the list.

At the very bottom is where you set the path for a USB or FireWire (IEEE-1394 or i-link) Mass Storage camera. This box becomes active once you select USB or FireWire Mass Storage camera in the camera list. You need to enter here the path where you mount the camera, usually "/mnt/camera" or "/mnt/removable".

To be able to use your digital camera with &digikam;, connect the camera to your computer, switch the camera to the image display mode and turn it on.

Try and see if &digikam; can auto-detect the camera; if not, you can set the camera model and port manually. Once you have the camera setup, go to the "Cameras" menu in the main interface and you will see the camera listed in the menu.

You can choose any title you like for the camera in the setup and this title will be used in the main window Cameras menu. If you have more than one camera, you can add them through this setup interface.

##### Miscellaneous Settings

With the Confirm when moving items to trash setting you can set the verbosity of &digikam; when you delete a photograph or an Album. See Deleting a Photograph and Deleting an Album sections for more details.

The editorial changes done through the right sidebar can be quietly applied by &digikam; when setting the Apply changes in the right sidebar without confirmation option. Otherwise the changes must be applied by pressing the Apply changes button.

You can also switch off the display of the splash screen when &digikam; loads. This may speed up the start time of &digikam; slightly.

Scan for new items at startup option will force &digikam; to scan the album library tree for new items added or removed between &digikam; sessions. This may slow down the start time of &digikam;. If any items have been removed from album library, &digikam; will ask you confirmation before to remove definitely item references in database.

#### The Theme Setup

Color schemes are supplied like themes to personalize &digikam; main interface for you pleasure. To access these settings select Settings Themes from the menubar and select your preferred theme to use.

## The Image Editor

### Introduction to Image Editor

#### The Image Editor Window

&digikam; incorporates a fast Image Editor with a few basic yet powerful image editing tools. You can use the Image Editor to view your photographs and to make corrections and alterations. The Image Editor can be accessed either by clicking on a thumbnail in the Image Window or by right-clicking on a thumbnail and selecting Edit from the context menu.

The Image Editor provides a number of tools that enable you to adjust a photograph. Some of these tools are provided by plugins to &digikam;. So they may not be available by default on your distribution. See the Setup Image Editor Section for more details about Kipi-plugins.

##### The Image Editor Window

The Image Editor Window

The image editor has just one main window with:

- A status at the bottom which shows the filename, the current file number, the current zoom level, and the current image size.

- A menu bar across the top and below that a tool bar that provides quick access to some commonly used functions.

The Image Editor Toolbar

1. First Current Album Image.

2. Previous Image.

3. Next Image.

4. Last Current Album Image.

5. Save the modified image.

6. Undoing last action.

7. Redoing previous action.

8. Restore the Current Image From Disk.

9. Zoom Into the Image.

10. Zoom Out of the Image.

11. Toggle Auto Zooming (if selected image will fit in the window).

12. Rotate the Current Image.

13. Crop Image to the Selected Region.

#### Restoring Your Original Photograph

The editing functions of the Image Editor will make changes to your photograph. None of the editing functions will change the original photograph unless you select File Save or click the Save button in the tool bar. Note that once you have saved the changed version you will not be able to recover the original photograph.

You might prefer to take a copy of your photograph before you make any changes. You can use File Save As to save a working copy.

At any time before you save your photograph you can restore the view to the original image by selecting File Revert or clicking the The Image Editor Revert Button Revert button on the tool bar. You will lose any changes that you have made to the photograph since it was last saved.

#### Undoing/Redoing Actions

Almost anything you do to an image in Image Editor can be undone/redone. You can undo the most recent action by choosing Edit Undo, and redo by Edit Redo

If these are done frequently, you really should memorize the keyboard shortcuts, &Ctrl;-Z to undo an action, and &Ctrl;-Shift-Z to redo an action.

You have to press the &LMB; over the undo or redo icon in the tool bar and hold it down for a moment to produce a context menu. If you choose one of the menu items, all undo/redo actions until the chosen ones are undone/redone.

#### Moving Between Photographs

Once you have started the Image Editor you can move between photographs in the same view you started from by using the navigator buttons on the toolbar, PgUp, PgDown or the entries in the File menu. If you have made any changes to the current photograph you will be asked if you want to save them.

#### Changing the View

You can zoom in and out of a photograph using the &Ctrl;scroll wheel, the toolbar icons or the entries in the View menu.

To make a photograph fit the window use this button on the tool bar: Zoom Autofit The Image Editor AutoFit Button

View Full Screen Mode will display the photograph using the full screen mode. You can move back to the normal view by pressing the &Esc; key. By default the toolbar is still displayed even in Full Screen Mode. If you would prefer that the toolbar is not displayed you can turn it off in the Configure &digikam; dialog accessed from the main &digikam; window, see the Setup Image Editor Section.

#### Printing Images

When you want to print the current image from the Image Editor, select File Print image (&Ctrl;+P) and you get the standard &kde; Print dialog, where you can adjust the settings before printing your photograph.

From the main window view you can print single images or whole sets of them. Entire thumbnail pages can be printed with your selection. All you need to do is selecting images the standard way and call Image Print Assistant. Then follow the instructions and choices to make.

&doc-photo-editing; &doc-color-management;
&doc-menu-descriptions; &doc-credits-annexes;

## Installation

### How to Obtain &digikam;

The website for &digikam; is at http://www.digikam.org. Please check it regularly to get the latest news about &digikam;. &digikam; can be obtained in binary and source format from the digiKam web site.

Also you can checkout the digikam and kipi source code modules from &kde; Extragear Git repository like this:

        % git clone git://anongit.kde.org/digikam
        % git clone git://anongit.kde.org/digikam-doc
        % git clone git://anongit.kde.org/kipi-plugins
        % git clone git://anongit.kde.org/kipi-plugins-doc

The last releases can be downloaded at this &URL; ftp://ftp.kde.org/pub/kde/unstable/digikam/.

### Requirements

In order to successfully use &digikam;, you need the following digiKam dependencies. All library dependencies require development and binary packages installed on your computer to compile &digikam;.

Most likely your distribution vendor might already have packaged and provided these packages.

### Compilation and Installation

In order to compile and install &digikam; on your system, type the following in the base folder of the libkipi and digikam module distributions. You should use a separate build folder to help cleaning up sources if something goes wrong.

        % mkdir build
        % cmake -DCMAKE_BUILD_TYPE=debugfull -DCMAKE_INSTALL_PREFIX=`kde4-config --prefix` ..
       % make
        % su
        % make install

#### Important Notes

Stage 3 is required if you are installing libkipi/libkexiv2 in a non-standard location, and you must let pkg-config know about their paths.

More specific compilation and installation options can be passed to the cmake. Use `cmake --help` on the command line to view these options.

Use -DCMAKE_BUILD_TYPE=debugfull option with cmake for to provide a full information bug report.

Because &digikam; depends on libkipi and libkexif, you must build these libraries before you build &digikam;.

Since &digikam; uses CMake you should not have trouble compiling it. If you run into problems please report them to digikam-users@kde.org.

&documentation.index;