digiKam Configuration


digiKam tries to give you as much control over how it works as possible. There are many options that change the behavior of the application. To access these settings select SettingsConfigure digiKam... from the menubar. The configuration dialog is separated by categories displayed in separated pages. You can change between these pages by clicking on the icons on the left-hand side of the dialog.

Database Settings


For an introduction of internal data storage, please refer to Introduction of digiKam Databases section.

The Sqlite Database

SQLite is a relational database management system, contained in C programming library. SQLite is not directly comparable to client/server SQL database engines such as MySQL, Oracle or PostgreSQL. Rather, it is an embedded SQL database engine, i.e. it is embedded in an end program. SQLite reads and writes directly to ordinary disk files. For device-local storage with low writer concurrency and less than a terabyte of content, SQLite is almost always a better solution. SQLite is fast and reliable and it requires no configuration or maintenance. It keeps things simple. SQLite "just works".

By default, digiKam uses SQLite as its back-end for storing important metadata and thumbnails. Three SQLite files used for storing them are named respectively:

  1. Core: digikam4.db.

  2. Thumbs: thumbnails-digikam.db.

  3. Faces: recognition.db.

To make your application run fast and smoothly, it is recommended to check and optimize your databases once in awhile. This could be achieved using sqlite3 packages or sqlite browser (high quality, easy to use visual tool for managing database objects). For Ubuntu and its derivatives, it could be retrieved using sudo apt-get install sqlite3 or sudo apt-get install sqlitebrowser. Now all remains is to open the terminal, switch to the directory where databases are stored.


Take care to use a place hosted by fast hardware (such as SSD) with enough free space especially for thumbnails database. A remote file system such as NFS cannot be used here. For performance and technical reasons, you cannot use removable media.

SQLite database files could be found in your “collection” folder, which you have added to digiKam. (By default, if you add your “Pictures” collection, the database files will be present in ~/Pictures folder).

The MySQL Database

MySQL Versus SQLite

MySQL is an open-source, relational database management system, written in C and C++. Original development of MySQL by Michael Widenius and David Axmark beginning in 1994. Sun Microsystems acquired MySQL in 2008, which was later acquired by Oracle in 2010. MySQL currently works on almost all system platforms (Linux, Microsoft Windows, OS X, SunOS …).

MariaDB server is a community developed fork of MySQL server. Started by core members of the original MySQL team, MariaDB actively works with outside developers to deliver the most featureful, stable, and sanely licensed open SQL server in the industry.

MariaDB has actually overtaken MySQL, ‘cause of few basic reasons:

  1. MariaDB development is more open and vibrant.

  2. More cutting edge features.

  3. More storage engines.

  4. Better performance.

  5. Compatible and easy to migrate.

digiKam also provides support for popular MySQL database engine. Of course, you might wonder why you’d want to switch to MySQL when SQLite already does a good job of managing the data? MySQL offers many advantages for storing digiKam data, especially when collections include more than 100,000 items. With such large collections, SQLite introduces latency which slows down the application.

Using MySQL as digiKam’s database back-end allows you to store the data on local as well as remote server. Local, to replace the local SQLite storage and latter, to use a shared computer through network. Using MySQL as digiKam’s database back-end allows you to store the data on a remote server. This way, you can use multiple digiKam installations (For instance,on your notebook and PC) to access and manage your photo collections. You can also use MySQL tools to backup and analyze digiKam’s data.

To switch from SQLite to MySQL database, go to Settings / Configure digiKam... and then under Settings section, select a database from the drop down list.

  1. MySQL Internal: This allows to run an internal database server on your system. digiKam uses Unix socket for the connection.

  2. MySQL Remote: Use this if you’ve your data on remote server and you’re on a different machine trying to access the collection.

The MySQL Internal Server

While using a large collection, of size greater than 100,000 items, the application tends to slow down. To avoid the delay and maintain efficiency, digiKam provides option of using MySQL Internal Server”. To be clear, this isn’t an actual server, or a public network. Instead, it is a server that runs only while application is running.

Internal server creates a separate database that can be accessed (only while application is running) using the command: mysql --socket=/home/[user_name]/.local/share/digikam/db_misc/mysql.socket digikam

Internal server uses two MySQL Binary Tools - mysql_install_db and mysqld. You can configure their locations in the configuration dialog. digiKam will try to find these binaries automatically if they’re installed on your system.

The MySQL Remote Server

Obviously, to use digiKam with a remote MySQL, you would require a MySQL server. Or, you could also install MariaDB, which serves the purpose well. (Could be installed easily using this link.)

Follow the instructions below, if you don’t have a dedicated user account and a digiKam database already set up. Run the commands in MySQL server (after replacing password with correct one):


You can select any database name. (Here it is, “digikam”). Just remember to fill in the database name correctly in Core, Thumbs, Face database names from the dialog box shown below.

                CREATE USER ''@'%' IDENTIFIED BY 'password';
                GRANT ALL ON *.* TO ''@'%' IDENTIFIED BY 'password';
                CREATE DATABASE digikam;
                GRANT ALL PRIVILEGES ON digikam.* TO ''@'%';
                FLUSH PRIVILEGES;


If you have an enormous collection, you should start the MySQL server with mysql --max_allowed_packet = 128M

Now, in digiKam, go to SettingsConfigure digiKam... and then under Settings section, select MySQL Server from the drop down list.

Enter the IP address of your MySQL server in the Host Name field and specify the correct port in the Port field (the default port is 3306).

In the Core Db Name field, enter the name of the first database for storing photo metadata.

Specify the name of the second database for storing wavelets compressed thumbnails in the Thumbs Db Name field.

The third database is dedicated to store face histograms for recognition purpose. Use the Face Db Name field for that.

To be connected safety to the remote server, enter your MySQL identification using username and password fields.

To check whether the database connection works properly, press the Check Connection button. If everything works as it’s supposed to, switch to the Collections sections, and add the directories containing your photos. Hit OK, and wait till digiKam populates the databases with data from photos. This can take a while if you have a lot of items to register in database.

There are some tips and recommendation to obtain the best results with a remote MySQL database server.

With slow network, digiKam hangs a lot of time especially when album contains many items (>1000). This solution relies on network performance. Problem has been reproducible using Wifi connection, for instance. Switching to Ethernet must solves the problem.

Also, if you have an enormous collection, you should start the MySQL server with mysql --max_allowed_packet = 128M. (If you’re well acquainted with using MySQL, you could also change your settings in my.ini or ~/.my.cnf files).

Database Migration

The photo management application comes up with an exclusive tool “Database Migration”, that allows users to migrate their data. Suppose, you’re using SQLite and you wish to move all data to MySQL database, migration tool will help you do so. It can help you migrate data from SQLite to MySQL and vice versa.

To migrate to another database, go to SettingsDatabase Migration.... A dialog box appears:

Now choose appropriate database types you want to convert to. Finally, click on Migrate button to convert the database from SQLite to MySQL (or vice versa).

Database Backup Recommendation

For security reasons, planing a database backup using crontab over the network can help against device dysfunctions. A NAS or an external drive can also be used for that.

Each database can be named with a different name, not only "digikam". This permits user to backup only what is needed. For instance, naming “core” database as digikamCore, permits to isolate only this table (the most important file). Thumbnails and recognition databases can always be regenerated for scratch.

The chapter about digiKam Maintenance tool will explain how to maintain in time the database contents and how to synchronize the collections with databases information (and vice versa).

Database Statistics

digiKam provides a unique tool of maintaining the statistics of your collection. It includes count of images, videos (including individual count by image format), tags etc. Also, includes the Database backend (QSQLITE or QMYSQL) and the Database Path (where your collection is located).

You can view your statistics by going to HelpDatabase Statistics. A dialog box like this will appear:

Collections Settings

This dialog manages your Album Collections. Each Collection represents a root folder containing your photographs or videos. Usually the root folder will contain sub folders. All these folders we call Albums. How to work with them, create, delete, rename them etc. is described in detail in the Albums View section.

Views Settings

In a number of tabs you can access the following groups of settings for the Views of digiKam (Albums, Tags, Labels, ...):

Icon Settings

The first series of settings on the left side of this view permit to customize the technical information shown below the icon thumbnail, as the filename, the file size, the creation date, the image dimensions, and the aspect ratio.

Note that the Show file modification date option shows the file modification date only if it's different from the creation date. This function is useful to identify quickly which items have been modified.

On the right side, the options permit to customize other properties to show over and below the icon thumbnail, as the file mime-type, the title, the caption, and the labels.

The Show rotation overlay buttons option shows overlay buttons over the image thumbnail to be able to process left or right image rotation.

The Show fullscreen overlay button option shows an overlay button over the image thumbnail to open it in fullscreen mode.

The Show Geolocation Indicator option shows an icon over the image thumbnail if the item has geolocation information.

An example of an icon is given below:

On the bottom side of this settings panel, you can tune the behavior of the icon with user actions.

The Thumbnail click action option permits to choose what should happen when you click on a thumbnail. Two settings are available: Show preview to display the image in preview mode (F3) or Start image editor to open the image in a separate editor window (F4).

The Icon View font option permits to select the font used to display text in icons.

The Use large thumbnail size for high screen resolution option renders the icon-view with large thumbnail size, for example in case of 4K monitor is used. By default this option is turned off and the maximum thumbnail size is limited to 256 x 256 pixels. When this option is enabled, the thumbnail size can be extended to 512 x 512 pixels. This option will store more data in the thumbnail database and will use more system memory. digiKam needs to be restarted for the option to take effect and the Rebuild Thumbnails option from the Maintenance tool needs to be processed over all collections.

Tree View Settings

These settings permit to customize the tree views of the Left and Right Sidebar. The Tree View icon size option configures the size in pixels of the Tree View icons in digiKam's sidebars. Use large value for HiDPI screen. The Tree View font option sets the font used to display text in Tree Views. The option Show a count of items in Tree Views will display the number of items inside a folder or assigned to a tag behind the album/tag name. The count shown depends on whether the subfolders/-tags are folded out or not and on the ViewInclude Album Sub-Tree and the ViewInclude Tag Sub-Tree settings in the main menu.

Preview Settings

Instead of opening the image in the editor, the digiKam preview mode (F3) will show the image within the main window in the Image Area. The advantage of the preview is that it is faster than opening the image editor and that the icons of the other images remain visible so that you are able to review the list of current images quickly. Depending on your computer features, you can customize the best way to load images into the preview. Raw files can be processed differently, as this kind of container can require long computation.

The first option will try to open a small version of the photograph embedded in the file. It will be found in all RAW files and can be found in all files that support IPTC or XMP like PNG, JPEG, TIFF, JPEG2000, PGF. If an embedded preview cannot be found some image decoders (JPEG, JPEG2000, and PGF, WebP) are able to create a reduced version of the photograph by themselves which is still faster than using the whole image. Depending on the size of the image, the size of the embedded preview and the size available for the preview on your screen the effect of this option can be visible or not.

The second option will always use the full image data for the preview regardless of whether there is a reduced version embedded in the file or not. This can result in a better quality of the preview but is usually slower.

Only if the second option is checked the drop down field to the right of "Raw images:" is accessible. It offers three options: With Automatic selected the Libraw decoder will decode the RAW data automatically without any adjustments from the user. This may lead to weird results sometimes. The algorithm also takes screen resolution and CPU speed into account to achieve an optimum regarding speed and rendering quality. Embedded preview will try to use the (JPEG) preview embedded in RAW files. Raw data in half size will show unprocessed RAW data in half size.

The option Preview is zoomed to the original image size is related to the first option. It will zoom the embedded view to the original image size which can lead to a reduced quality of the preview depending on the parameters mentioned above in the description of the first option.

The option Show icons and text over preview will show icons for rotation, face tags, full screen mode, etc. in the top left corner of the image preview and a text indicating which data the preview is showing in the top right corner.

Full-Screen Settings

The options in this tab apply only to the Full Screen Mode you can access via the Full Screen button on the Toolbar or via ViewFull Screen Mode (Ctrl-Shift-F) in the main menu or the context menu. It does not apply to the Full Screen Mode you access by clicking the Show Fullscreen icon either on a thumbnail or on the preview.

If all three options are activated the only way to leave the Full Screen Mode is the context menu or Ctrl-Shift-F. You can work on the images also by choosing functions from the context menu of an icon or the preview.

Mime Types 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.

For more information, for example how to remove file types from the list, use the context help with the question mark from the window header.

Album Categories Settings

In the Album View you can choose from ViewSort AlbumsBy Category to have the Albums in the Album Tree of the Left Sidebar sorted by category. Here you can manage these categories, which is add or remove categories or rename them by using the Replace button. To assign categories to an Album you got to use the Album Properties dialog.

Tooltip Settings

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

See below an example of the information displayed in a tooltip over an icon with the relevant settings done in the configuration page.

Metadata Settings


Image files can have some metadata embedded into the image file format. These metadata can be stored in a number of standard formats as JPEG, TIFF, PNG, JPEG2000, PGF, and RAW files. Metadata can be read and written in the EXIF, IPTC, and XMP formats if they are present in the file.

Behavior Settings

The Behavior tab allows you to select what information digiKam will write to the metadata and control how digiKam will deal with this embedded information.

If the lazy synchronization is turned on digiKam will only write metadata when user clicks on the Apply pending changes to metadata icon in the status bar or on exit.

Sidecars Settings

The Sidecars tab allows user to control whether digiKam will read/write from/to XMP sidecars or not. Filename for the sidecars set to filename.ext.xmp. For example, image1.dng will have a sidecar file named image1.dng.xmp.

Please Note: If the box "Read from sidecar files" is checked digiKam will only read the sidecar while ignoring the embedded metadata.

Rotation Settings

Rotate Actions

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 click with the right mouse button 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 metadata. digiKam can read this tag to adjust the image accordingly. If you manually rotate an image, these metadata 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.

Views Settings


Advanced Settings

The Advanced tab allows you to manage namespaces used by digiKam to store and retrieve tags, ratings and comments. This functionality is often used by advanced users to synchronize metadata between different software. Please leave the default settings if you are not sure what to do here.

Templates Settings

The Metadata Templates Manager is meant to create and manage metadata templates which can be used in

  • the Information tab of the Captions view of the Right Sidebar

  • the On the Fly Operations (JPEG only) section of the Settings view of the Right Sidebar in the ImportCamerasOneOfMyCameras Window.

The top part shows a list of the already existing templates. The first row shows the title of the template, the second row shows the name of the author(s) in the Author Names field of that very template. To the right you have three editing buttons, below an input field for the template title. To create a new template you type a title in the input field and click the Add... button. The new template will appear in the list. To edit an existing template you select it in the list, then you edit its fields (see next paragraph) and finally you click the Replace... button. You can as well type in a new title for the edited template and save the new version with the Add... button. To delete a template, very obviously, you select it in the list and click the Remove button.


Note that all the changes you made to the templates will only be stored in the template file if you exit the settings dialog with OK! The Add... and Replace... buttons only change the template list in the RAM.


The template file can be found in ~/.local/share/digikam/ for manual backup or for managing different template sets by means of the file system.

The rest of the window is divided into four tabs, grouping the metadata fields into Rights, Location, Contact and Subjects.

The Rights tab (see above) contains the default identity and copyright data. This is an extract of the IPTC specifications for these fields:

  • 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 (c) {date of first publication} name of copyright owner, as in "(c)2005 John Doe." Note, the word "copyright" or the abbreviation "copr" may be used in place of the (c) 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."

The fields in the Location tab are self explaining by their title and the gray hints in the empty fields. A little bit more elaborate description can be found under SettingsConfigure digiKam...MetadataViewsIPTC viewer

The data in the Contact tab refer to the (lead) photographer under Author Names in the Rights tab.

In the Subjects tab you can assign one or more Subject Codes according to the IPTC Photo Metadata Standard to the template. If the first option Use standard reference code is selected you can choose a code from the drop down field and the meaning of it will then appear in the fields of the Use custom definition section. If you don't know the code for the subject you want to assign this way is a bit tedious since there are 1400 subjects in the standard. A better way is to look for your subject in this URL. There you select Subject Codes and your language (English recommended) and click Show. In the diagram you scroll and make additional levels of an item visible by clicking on one of the fields. In the field right of the diagram you can find the code of the selected subject.

In general the IPTC Subject Codes are quite comprehensive but on the other hand a bit incomplete in some fields, e.g. under Lifestyle and Leisure/Games you find just Go, chess, bridge and shogi. So you may want to add own subjects, even though they always remain private (or company) subjects. A way to do that in digiKam is to first check Use standard reference code and select 10001004 which brings you to Lifestyle and Leisure/Games/shogi - just to stay in our example. Then you check Use custom definition and change the last digit of Reference: to 5 and the text in the Detail: field to - say domino. You save this custom definition to the template by clicking Add... at the right side of the subjects list. Then you type in a template title (if it's a new template) and save the template by clicking Add... at the right side of the templates list. Don't mix up these two!

Image Editor Settings

Editor Window 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. The thresholds for over- and under-exposure can be set by the adjustment bars "... percents". Check Indicate exposure as pure color if you want only pure black (RGB 0,0,0) indicated as under-exposure and only pure white (RGB 8 bit 255,255,255 respectively RGB 16 bit 65535, 65535, 65535) indicated as over-exposure.

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). At the time of writing, metadata is supported.

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). At the time of writing, metadata is supported.

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. At the time of writing, metadata is supported.

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 supported.

With the LossLess PGF 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-2000. At the time of writing, metadata is supported.

Image Versioning Settings

Non-Destructive Editing and Versioning gives you the freedom of editing your images, trying out whatever you want without worrying that you might regret later what you did. digiKam takes care of the original and every important intermediate step if you want.

In the checkbox at the top you can enable or disable Non-Destructive Editing and Versioning.

In the first field you can choose the file format used for saving the intermediate steps and the final result. Remember that JPEG - like in the screenshot above - is a lossy format. So if you need to start over from an intermediate step it wouldn't be really non-destructive. If you can afford it in terms of space on the harddisk and loading/saving speed you better choose a lossless format like PNG or PCF for instance. Please click the information button on the right side for more detailed information.

In the next field you can decide whether the editor will save changes automatically on exit or should ask first.

In the third field you decide on which occasions you want the editor to save intermediate steps. Please click the information button on the right side for more detailed information.

In the last field you can adjust whether you want only the last version to be shown in the Image View (default, none of the boxes checked) or if you also want to see icons of the original version and/or intermediate steps.

RAW Decoding 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 when opening RAW files.

Fast and simple, as 8 bit image

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 the Auto Brightness setting will be taken into account (dcraw limitation).

Use the default settings, in 16 bit

If enabled, all RAW files will be decoded to 16-bit color depth using a linear gamma curve and according to the settings in the RAW Default Settings tab. To prevent dark image rendering in the editor, it is recommended to use Color Management in this mode.

Always open the Raw Import Tool to customize settings

With this option checked the Raw Import Tool will open at the Right Side Bar in the Image Editor so that you can set individual parameters for every image you open.

RAW Default Settings


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.

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.

Do not stretch or rotate pixels



TODO 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.



Refine interpolation

This option is available only for DCB and VCD/AHD. TODO

White Balance


Four options are available here: Default D65, Camera, Automatic and Manual. Default D65 reflects normal daylight conditions. Camera uses the camera's custom white-balance settings if set. ??? Automatic The default is to use a fixed color balance based on a white card photographed in sunlight. ??? Manual will adjust colors according to the T(K) (color temperature in degrees Kelvin) and Green settings. TODO


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.

Exposure Correction (E.V)


Correct false colors in highlights


Auto Brightness



Noise Reduction

TODO 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.

Color Management Settings

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 rendering 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 e.g. "/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. Note: 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:

CameraProfile series
Canon 1D mark II6051
Canon 1D mark II6111
Canon 1Ds6021
Canon 1Ds mark II6081
Canon 5D6091
Canon 10D6031
Canon 20D6061
Canon 30D6112
Canon 40D6101
Canon 300D6031
Canon 350D6111 or 6071
Canon 400D6131

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.

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).

Synchronize panels automatically refers to the Synchronize button on the Light Table toolbar which is to say that you can still switch off this option there. If the next option is not checked you have to load the images from the thumbbar to the two panels of the Light Table by drag+drop or with the On left or On right buttons.

Slide-Show Settings

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.

Image Quality Settings

These settings refer to the Image Quality Sorter tool which you can access via ToolsMaintenance.

Through the first checkbox you can enable or disable the whole function. With the four Detect ... options you can choose which kind of fault should be factored in by the Image Quality Sorter. Talking about factoring in: the factors for blur, noise and compression can set with the help of the three ... Weight adjustment bars at the bottom.

With the three Assign ... Label ... options you can decide to which image quality level a label should be assigned. Un-checking all three of them renders the Image Quality Sorter useless, of course. The thresholds for these levels can be set through the three ... threshold adjustment bars. It will normally take some testing and trying out to find the settings that suits your needs. Note that the input, i.e. the images the process has to investigate, will have quite some influence. It's a difference whether you choose an album containing images which are all more or less o.k. and have only minor differences or if you present a collection of pictures where some of the pictures really have some bad blur, noise, ... You also have to consider at which point of your workflow you want to perform this operation. Right after importing the files from your camera is probably a good idea.

With the topmost of the adjustment bars you can adjust the speed of the process in three steps. Slow speed (1) should lead to better results.

Camera 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

General Settings

With the String comparison type setting, you can set the way in which strings are compared inside digiKam. This influences the sorting of the tree views. Natural tries to compare strings in a way that regards some normal conventions. The result will be sort naturally even if they have a different number of digits inside. Normal uses a more technical approach. Use this style if you want to entitle albums with ISO dates (201006 or 20090523) and the albums should be sorted according to these dates.

With the Confirm when moving items to trash and Confirm when permanently deleting items settings 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.

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.

Application Behavior Settings

With the Scroll current item to center of thumbbar setting, you can force thumbbar to center current selected item with mouse pointer on the center of visible area.

With the Show splash screen at startup setting, you can switch off the display of the splash screen when application loads. This may speed up the start time slightly.

With the Sidebar tab title setting, you can set how sidebars on the sides will show the tab titles. Use Only For Active Tab option only if you use a small screen resolution as with a laptop computer. Else For All Tabs will be a best choice to discover quickly all internal features of digiKam.

With the Widget style setting, you can choose the default application window decoration and looks. Fusion style is the best choice under all desktop.

With the Icon theme setting, you can choose the default application icon theme. Theme availability depends of desktop used to run digiKam.

The Theme Setup

Color schemes are supplied like themes to personalize digiKam main interface for you pleasure. To access these settings select SettingsThemes from the menubar and select your preferred theme to use.

Configure Shortcuts

digiKam has the common KDE shortcut configuration tool accessed via the SettingsConfigure Shortcuts main menu item. For more information read the section about the shortcut configuration in KDE applications of the KDE Fundamentals.

digiKam keyboard shortcuts by default:

Rating assignment

no ratingCtrl+0
1 starCtrl+1
2 starsCtrl+2
3 starsCtrl+3
4 starsCtrl+4
5 starsCtrl+5

Pick label assignment

Pick LabelShortcut

Color label assignment

Color LabelShortcut


Zoom inCtrl++
Zoom outCtrl+-
Zoom 100%Ctrl+.
Fit to windowCtrl+Alt+E
Fit to selectionCtrl+Alt+S

General shortcuts

Delete items permanentlyShift+Del