Archive for January 2013
Correct Lens Distortion in GIMP with GimpLensfun
While GIMP offers a wide range of tools for working with photos, it lacks one feature that is essential for serious photographers: the ability to automatically fix lens distortion. Fortunately, the GimpLensfun plugin fills the void quite nicely.
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Process Film Negatives with digiKam
While digiKam is first and foremost an application for processing and organizing digital photos, it also features tools for working with film negatives.
Before you can process negatives in digiKam, you need to digitize them. If you don’t have access to a film scanner or a lab that offers film scanning services, you can digitize film using a DSLR camera (there are plenty of tutorials on how to do that on the Web). The rest of the process assumes that you are using the latter way to digitize film negatives.
Open a RAW file containing a film negative in the editor (choose Tools → Image Editor or press F4). Crop the original file and apply lens correction if necessary. Choose then Color → Invert to transform the negative into a positive image. In case you work with the color negative, the converted image most likely requires some additional tweaking. First of all, the converted image is likely to have a strong blue tint. The easiest way to remove it is to use digiKam’s Auto-Correction tool. Choose Color → Auto-Correction and select one of the presets. In many cases, the Auto Levels or Equalize presets do a decent job of correcting the colors. If the colors still look slightly off, you can adjust them further using the Colors → Color Balance tool.
Using the Color Negative tool
The Invert feature in combination with an Auto-Correct preset provides a quick-and-dirty way of converting negatives, but digiKam has another tool designed specifically for processing color negatives. To access it, choose the Color → Color Negative command. The Color Negative Film interface contains several handy features that can help you to convert the negative and tweak the resulting image. While the Invert tool uses a generic profile for converting negatives, the Color Negative Film interface offers film profiles for many popular film types. So the first step is to select the appropriate profile. For better results, try to enable the Color Balance option, too. If the used film is not in the list, you can use the Neutral profile as a fall back.
Although choosing the matching film profile may yield a better result, the converted image may still require some work. In most cases, you may need to adjust the white point to remove the remaining blue tint. You can do this either manually or automatically using the appropriate buttons. Usually, the automatic white point adjustment does the job, but the resulting image needs to be brightened up by adjusting the Gamma input value slider.
Sophie in North Korea
The longer I think about what we saw and heard, the less sure I am about what any of it actually meant.
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Slow-Photography Movement
[...] while taking photos has become a way to mark almost any moment, there is often an unnoticed tradeoff. Photography is so easy that the camera threatens to replace the eyeball. Our cameras are so advanced that looking at what you are photographing has become strictly optional. To my surprise, no monument I saw in Israel could compete with the back of the camera. What gets lost is the idea that photography might force you to spend time looking at what is in front of you, noticing what you might otherwise ignore.
All this has spawned a rebellion that I consider myself part of: Call it the slow-photography movement.
Continue to read The slow-photography movement asks what is the point of taking pictures?
Calibrate and Profile Monitor for Use with digiKam
To calibrate a monitor and generate a color profile for it on Linux, you need two things: a colorimeter and color profiling software. High-quality professional colorimeters tend to be rather expensive, but you can use the excellent open source ColorHUG device instead. When it comes to calibration and profiling, the displaycalGUI software is the perfect software for the job. It provides a graphical user interface to the display calibration and profiling tools of the Argyll CMS open source color management system. The latter is available in the software repositories of most mainstream Linux distributions, so you can install it using your distro’s package manager. On Debian and Ubuntu-based distributions, this can be done by running the apt-get install argyll command as root. Grab then the packaged version of dispcalGUI from the project’s website and install it on your system. Connect ColorHUG (or any other supported colorimeter) to your machine and launch dispcalGUI.
dispcalGUI
Press the Refresh button to make dispcalGUI detect the connected colorimeter (it should appear in the Instrument/Port section). If you are using a multi-display setup, make sure that the correct monitor is selected in the Display device section. Select then Photo from the Settings drop-down list. Press then the Calibrate & Profile button and follow the instructions to calibrate the monitor and generate its color profile. Once the color profile has been generated, dispcalGUI prompts you to install the profile and enable it during boot.
Launch then digiKam, choose Settings → Configure digiKam, and switch to the Color Management section. Click on the Profiles tab, select the generated profile from the Monitor profile drop-down list, and press OK to save the settings.
Photo of the Day: The Path of Least Resistance
I wanted to do an Arduino-based project, but ended up with this. Taken with Nikon D90 and Nikkor 50mm f/1.8 D. Processed in digiKam. Shutter speed: 1/60 sec. Aperture: f/9 ISO: 200
The Path of Least Resistance
The photo is published on Wikimedia Commons under the Creative Commons Attribution-ShareAlike 3.0 Unported License.
Wikimedia Commons:
http://commons.wikimedia.org/wiki/File:The_path_of_least_resistance.jpeg
Track Photo Locations on Android Device using GPS Map
The GPS Map app can turn an Android device into a handy tool for keeping track of locations you’ve already photographed or plan to photograph later. The app allows you to add so-called placemarks to the map, and you can use photos stored on your Android device as markers.
Adding a placemark in GPS Map requires several steps, but ultimately it’s a rather straightforward thing to do. Long-tap on the desired location on the map and tap Yes. Tap then Marker → Import Image. To import an existing photo, tap Gallery (or Browse) and select the desired photo.
Adding a photo to a placemark
If the selected photo contains geographical coordinates, you can attach the photo to the current placemark using the Import Image button, or you can import the photo as a new placemark by tapping on Import Image & Placemark.
Once you’ve attached the photo to the placemark, return to the Placemark Edit screen, modify the default description is necessary and tap the Confirm button to add the placemark. You should then see the placemark with a tiny thumbnail of the attached photo on the map. You can create as many placemarks as you need and use the Settings → Placemarks screen to manage existing placemarks.
GPS Map’s interface is somewhat unpolished, and the app can be slow at times, but if you are looking for a tool that can help you to track locations in an efficient manner, then the app is just the ticket.
Import Photos from a Remote Server into digiKam
Using commands under the Import menu, you can pull photos from a variety of sources, including remote servers. The latter functionality in digiKam is provided through the KioExportImport Kipi plugin which supports common protocols like FTP, SSH, and SMB.
To pull photos from a remote server, choose the Import → Import from remote computer command. In the import dialog window, press the Add Images button to open the Select Images dialog. There are two ways to access photos stored on a remote server. If the machine runs on the local network, you can access it by choosing the Network item in the Places panel (if the panel is not visible, press F9 to enable it). This will show all shares and services available on the local network. Navigate then to the desired share and select the photos you want to import.
Importing photos from a remote server
To access remote servers outside your local network, click on the Location field and enter the server’s URL. The URL must start with the protocol prefix (e.g., fish:// (for the SSH protocol or smb:// for the SMB protocol).
Once you’ve located the source directory, select the desired images and press Open to add them to the list of imported photos. In the My Albums pane, select the target album (or create a new one), and press the Start Import button to import the photos into digiKam.
Photo of the Day: Renzu-san
I bought a set of snap-on smartphone lenses which turned out to be total crap, so I found a new use for them. Meet Renzu-san (or Mr. Lens). Taken with Nikon D90 and Nikkor 50mm f/1.8 D. Processed on Nexus 7 using Photo Mate and Snapseed. Shutter speed: 1/60 sec. Aperture: f/7.1 ISO: 200
Renzu-san
The photo is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License.
