While digiKam can’t handle Adobe Photoshop curve presets directly, the application supports curves in the GIMP-compatible CRV format. So if you want to use Adobe Photoshop curve presets with digiKam, you have to convert them into .crv files — and the acv2gimp.py Python script can help you with that. Before you put the script to use, make sure that Python is installed on your system. Next, use the chmod +x acv2gimp.py command to make the script executable. Once you’ve done that, you can convert a curve preset by running the ./acv2gimp.py command followed by the name of the file in the ACV format:
By default, the converted file has the same name as the original preset sans the file extension (e.g., curvepreset.acv becomes curvepreset), but you can use the -o parameter to specify a different name:
./acv2gimp.py -o converteredcurvepreset.crv curvepreset.acv
To load the converted curve preset in digiKam, open a photo for editing and choose Colors → Curves Adjust. Press then the Load button and select the converted curve.
Starting with version 2.6, digiKam features the Tools → Maintenance menu which gives you access to tools designed to perform a variety of housekeeping tasks: from scanning for new photos to running a face recognition action. Here is a brief overview of the available tools.
Scan for new items This command scans the collections for newly added photos. By default, digiKam does that automatically on every start. But if you’ve disabled this feature to speed up digiKam, you can use the Scan for new items tool to add new photos manually.
Rebuild thumbnails If, for some reason, thumbnails in albums are missing or broken, you can use this tool to fix them. To speed up this action, enable the Scan for changed or non-cataloged items option. This will ignore photos which have already been processed and catalogued.
Rebuild fingerprints digiKam uses fingerprints for certain search actions, and this tool allows you to generate or rebuild fingerprints. Enable the Scan for changed or non-cataloged items option to skip the already processed and cataloged photos.
Find Duplicate Items Need to find duplicate photos? This command can help you with that. Note that this action uses fingerprints, so you might need to run the Rebuild Fingerprints action prior to using this tool.
Sync image metadata with Database When digiKam adds new photos, it automatically reads metadata from each photo and writes them into its database. The Sync image metadata with Database tool does the opposite: it reads metadata from the database and writes them into photos or into so-called XML sidecar files. This feature can come in handy in many situations. You can use it, for example, to back up metadata from the database to XML sidecar files.
Face Detection This tool finds photos containing faces and attempts to recognize person or persons in each photo. (see the Face Recognition article for more info.)
Sharing is caring, and there is probably no better way to share your photographic masterpieces with the world than adding them to the Wikimedia Commons pool. While the project’s website features its own tool for uploading photos, digiKam’s Wikimedia Export Kipi plugin can come in rather handy when you need to export multiple photos in one fell swoop without leaving the convenience of your favorite photo management application.
Using the Wikimedia Commons Kipi plugin
The plugin can be evoked by choosing the Tools → Export to Wikimedia Commons command. If you don’t see the command in the menu, then you are either using an older version of digiKam (the plugin has been introduced in version 2.6) or the plugin has not been enabled. In the latter case, you can activate the plugin by choosing Settings → Configure digiKam. Switch then to the Kipi Plugins section and enable the Wikimedia Export plugin. Before you start using the plugin, you should also create an account with Wikimedia Commons.
Using the plugin to upload photos to Wikimedia Commons couldn’t be easier. Select one or several photos in a digiKam album and choose Tools → Export to Wikimedia Commons. This opens the export dialog window. In the Wiki field, type the URL of Wikimedia Commons API (http://commons.wikimedia.org/w/api.php). Enter then your user name and password in the appropriate fields and press Log In. In the Information section, specify the author’s name and choose a license. If you want to resize photos before uploading them to Wikimedia Commons, check the Resize photos before uploading check box, and adjust the quality and size settings. Hit the Start Upload button, and the plugin takes care of the rest.
Soft proofing is a technique which allows you to see what the photo will look like when printed using a specific printer and photo media (paper, canvas, etc.) without actually printing the photo. Many professional photo processing applications support soft proofing, and digiKam is no exception.
To make this feature work in digiKam, you need to specify color profiles for your display and the output device (e.g., printer). But before you do that, you need to obtain the ICC color profile for your specific printer and print media. Say, you are using an Epson 9880 printer to print photos on the IJMF professional glossy photo paper from Diamond Jet. Grab the appropriate ICC profile from the company’s Resources page. Create the ~/icc directory and move the obtained .icc file into it. In digiKam, choose Settings → Configure digiKam, switch to the Color Management section, and click on the Profiles tab. Select the desired color profile from the Monitor Profile drop-down list (the default sRGB IEC61966-2.1 color profile is a good choice in most cases). Next, in the Color Profiles Repository section, specify the path to the ~/icc directory. Press OK to save the changes and close the dialog window, then restart digiKam.
To enable soft proofing, open the photo you want for editing and choose View → Soft Proofing Options. Select the downloaded .icc color profile from the Profile of the output device to simulate drop-down list, then select the desired item from the Rendering intent drop-down list. This should generally be Relative Colorimetric, but if your printer supports only a limited gamut you may want to try the Perceptual rendering intent instead. Enable then the Highlight the out-of-gamut colors option and select the highlighting color you want. Finally, enable soft proofing by pressing the Soft Proofing On button, and you should see the photo exactly as it would appear in print.
Sometimes the best way to spice up a photo is to make it look faded, and digiKam makes it supremely easy to achieve this effect.
Open the photo for editing and choose Color → White Balance. Adjust exposure compensation to slightly overexpose the photo and set the color temperature to 12000 to add a strong golden tint to the photo. Press OK to apply the modifications. Choose then Color → Hues/Saturation/Lightness and set Saturation to -50. Press OK, and you are done. The described technique works particularly well with skin tones, so it’s suitable for use with portrait photos.
Adding a dash of color tint to a black and white photo can often produce a dramatic effect, and digiKam does have a handful of toning filters for you to try.
But you are not limited to the built-in filters: using digiKam’s editing tools, you can easily tint photos using whatever color you like. To do this, open a photo for editing, choose Color → Hue/Saturation/Lightness and set Saturation to -100. This effectively turns the image into a black and white photo. Press OK to save the changes, then choose Color → Color Balance. Usen then the sliders to create the toning color you want. Press OK, and you are done.
While digiKam won’t rival dedicated software for tethered shooting, you can use the application’s Import interface to trigger the connected camera and instantly fetch photos from it. This functionality can come in handy when you want to have an instant preview of photos you take on a large screen.
To make use of this feature, connect your camera to the machine running digiKam, and turn the camera on. In digiKam, choose Import → Cameras and select your camera model. You can then trigger the camera using the Capture button. There are a couple of things you need to keep in mind, though. digiKam can’t control camera settings (shooting mode, aperture, shutter speed, etc.) remotely, so you should set them beforehand. The images captured from within the Import interface are not stored on the camera’s storage card, so make sure you import them into digiKam before you disconnect or turn off the camera.
Besides a handful of minor tweaks, the new version of the digiKam Recipes ebook includes the following new material:
- Prevent Photos in digiKam from Disappearing
- Simple Color Toning
- Simulate a Washed Out Effect
Readers who already purchased the book will receive the new version free of charge. If you haven’t received your copy, please send your order confirmation as proof of purchase to firstname.lastname@example.org, and I’ll email you the latest version of the book.
Versioning in digiKam provides an excellent mechanism for non-destructive editing, but it does have a tiny quirk that can be a bit confusing if you are not aware of it. With the Versioning feature enabled, digiKam automatically displays only the most recent version of a photo and hides all the previous revisions, including the original file. This functionality helps to avoid clutter in the main thumbnail view, but this creature comfort can also cause panic when you all of a sudden can’t find the original photos. Fortunately, digiKam provides several ways of solving this conundrum.
Select the latest version of the photo, expand the Versioning right sidebar, and you should see all revisions of the selected image along with its original. If you want to make the original file visible in the thumbnail view, hover the mouse over the original’s thumbnail in the Versioning sidebar and click on the Show item permanently icon.
Alternatively, you can disable the hiding functionality altogether. To do this, choose Settings → Configure digiKam → Editing Images and untick the Always show original images and Always show intermediate snapshots check boxes.
Want to add a vintage effect to your photos? digiKam has all the tools you need to turn your digital snapshots into vintage masterpieces. Open the photo you want for editing, adjust exposure, white balance, and tweak other settings as you would usually do. The first step in the “aging” process is to add film grain to the photo. To do this, choose Effects → Add Film Grain. There are a lot of parameters you can configure, but you don’t have to enable and tweak them all. You can start with adjusting the Grain Size parameter as well as trying different values for parameters in the Luminance Noise section. You can preview the result at any time using the Try button. Next step is to tweak the color balance to make the photo look aged. One way to do this is to tweak the color balance settings, so the photo looks washed out with a slightly yellow cast imitating aged photo paper. Choose Color → Color Balance and adjust the Cyan, Magenta, and Yellow parameters to achieve the desired result.
The exact values for each parameter depend on the given photo and your personal taste, but you can start with the following values:
To make the vintage effect even more realistic, add vignetting to the photo. Choose Enhance → Lens → Vignetting Correction, tick the Add Vignetting check box and adjust the available parameters to your liking. Finally, sharpen the photo using Enhance → Sharpen to make the film grain more pronounced, and you are done.