Archive for June 2010
Install the Latest Version of digiKam on Ubuntu 10.04
Can’t wait till the latest version of digiKam appears in the official Ubuntu software repositories? You don’t have to: using the personal package archives (PPA) provided by the Launchpad service, you can install the latest release of digiKam with a few simple commands. Before you proceed, though, remove any previous version of digiKam installed on your machine. Also, to be on the safe side, delete all the related configuration files. You can do that using the Ubuntu Tweak tool.
Now you are ready to install the most recent version of digiKam. First, add the PPA containing the latest digiKam packages and the required libraries:
sudo add-apt-repository ppa:kubuntu-ppa/ppa
sudo add-apt-repository ppa:philip5/kde44
Update then the repositories:
sudo apt-get update
And install the digikam package:
sudo apt-get install digikam
That’s all there is to it. Launch digiKam by choosing Applications | Graphics | digiKam and enjoy the latest and greatest version of this powerful photo management application.
Improve Photos with digiKam’s Local Contrast Tool
digiKam offers several features that can improve photos containing under- or overexposed areas. For example, the Exposure Blending tool lets you merge multiple shots with different exposures into one perfectly exposed photo. But what if you have just a single image? In this case, you might want to give the Local Contrast feature a try. It’s based on the LDR Tonemapping utility which is designed to improve the dynamic range of the photo by reducing its global contrast and increasing the local contrast. It does so by generating a desaturated and blurred version of the photo. It then combines the RGB channels of the original photo with the desaturated blurred image using either the Linear or Power function. Sounds complicated? Don’t worry, the Local Contrast tool is rather straightforward to use, so you don’t have to understand all its intricacies in order to achieve pleasing results.
Open the photo you want in the editor and choose Enhance | Local Contrast. The tool lets you apply up to four tonemapping operations called stages. Each stage offers two parameters for you to tweak: Power and Blur. The former allows you to specify the desaturation level, while the latter lets you adjust the affected areas on the photo. To preview the result, hit the Try button. Once you are satisfied with the result, press OK to apply the process to the photo.
While the Local Constrast tool may sound like an easy way to fix photos, you should use it with care: sometimes it can do more damage than good, producing unnaturally looking photos.
Renaming Photos with digiKam
Giving your photos meaningful names makes it significantly easier to keep tabs on them. Of course, renaming each and every photo by hand is not particularly practical, especially if you take dozens or even hundreds of photos each day. This is when digiKam’s Rename feature can come in rather handy. You can use it to define rather advanced renaming rules and apply them to multiple photos in one fell swoop.
To put the Rename tool to practical use, select the photos you want to rename and press the Rename button in the main toolbar (you can also choose Image | Rename or press F2). The Rename dialog window offers a vast range of renaming options which allow you to create complex renaming rules. But you might want to start with a simple rule that renames photos using the date and time data. To do this, press the Date & Time button and select Image from the Source drop-down list. This will pull the date and time info from the photo’s metadata.
Next, you have to specify a date/time format by selecting the appropriate item from the Format drop-down list. If none of the available formatting options satisfy you, select the Custom item, which lets you construct the formatting string manually. For example, the yyyyMMdd-hhmmss formatting string produces file names like 20100531-173501 and 20100701-110111, while the MMM-dd-yyyy-dddd string generates names like May-31-2010-Monday and June-01-2010-Tuesday. The clever part is that you can immediately see the result of the renaming string right below the Format field. For a full list of available formatting options, check the official Qt documentation.
Besides date and time, the Rename dialog window offers a few other useful options. The Camera button, for example, allows you to add the camera model to the file name. This can be useful if you are using several cameras and you want to quickly identify photos taken with a specific camera. The Metadata button gives you access to EXIF and other photo metadata you can use in renaming rules.
Next to the field where you enter the renaming rule, there is a button that lets you specify so-called modifiers or actions that will be applied to the file names during the renaming operation. For example, using the Change Case modifiers, you can convert all file names to lower or uppercase, or capitalize the first letter. Here is a quick overview of other useful modifiers:
Trimmed – Removes leading, trailing, and extra spaces.
Unique – Adds unique numerical values to identical file names.
Replace – Performs search and replace. The modifier supports regular expressions.
Range – Lets you specify a specific fragment of the file name for the renaming rule. For example, the {5-} modifier in the [file]{5-} rule removes the first four characters of the file name, so IMAG0113.jpg, IMAG0351.jpg, and IMAG0573.jpg are renamed to 0113.jpg, 0351.jpg, and 0573.jpg
While digiKam offers a wide range of other features that can help you to keep tabs on your photos, it’s worth experimenting with the Rename tool. This way, you can quickly locate or identify specific photos even when digiKam is not running.
