So you've been convinced to make the leap from Photoshop to GIMP. You've downloaded the program, run the executable, figured out that old instructions decrying the difficult installation are outdated for the current version, but now what? Now, my GIMP Padawan, is when you start treating GIMP like it's Firefox and you get your plug-ins on.
What about GIMPshop, you say? No worries, as my Australian friends would say. We're going to take a look at the GIMP-plus-Photoshop mash-up, too.
In fact, let's take a look at GIMPshop first, because it sounds mighty tempting. It's a remix of the GIMP with some key extensions built-in to make it work more like Photoshop, and many tools have been renamed so that many of the Photoshop tutorials floating around out there are applicable to this open source competitor.
Although the bogarting of Photoshop tutorials is cool, the most noticeable change is the BackgroundWindow plug-in, which inserts a background window behind all active GIMP windows. When you use ALT+Tab to switch programs, for instance, you'll notice that you only have one GIMP icon. This is a welcome change, but it's not all it's cracked up to be.
GIMPshop is built off of an older GIMP, version 2.1. Some of the changes to the GIMP in the time between 2.1 and the current 2.4.2 are hard to ignore: the newer version loads faster, processes images faster, has a cleaner layout, refined tools, and comes with better pre-loaded plug-ins. Newer extensions either won't work well with GIMPshop, or they won't at all.
GIMPshop strikes a hard bargain between the upgrade sacrifices and the Photoshopesque style, but users who can accept that GIMP can do for free most but not all of what Photoshop can, I'd recommend giving GIMPshop a pass for the benefits of the newer versions of GIMP.
The GIMP features an enormous menu of available plug-ins. I'll be focusing on photography-centric plug-ins because, for better or worse, the GIMP keeps getting compared to Photoshop's photo-editing capabilities. For the photographer, the two most important are the RAW format plug-in, since GIMP doesn't handle 16-bit images natively, and the color profiles plug-in that UFRAW is based on.
UFRAW, which stands for Unidentified Flying RAW, can handle most of the most common RAW formats, including those from Canon, Nikon, Minolta, Olympus, Sony, Samsung, Pentax, and others. I found the plug-in to work as advertised: GIMP only recognized my Canon CRW files after the plug-in was installed, and I found the interface to be similar enough to Photoshop's as to not miss anything major.
Pandora is an excellent plug-in that gives you the power to create panoramas, combining multiple images through layers into one super-image that you can then save and edit. It's also an great tool for creating image collages, because users can manually adjust the alignment between the source images via the Move tool to create the exact effect they want.
Lomo is a plug-in that automatically oversaturates an image, taking its name from the popular Russian camera with the same effect. It works well, but it also highlights a drawback of many GIMP plug-ins: they often lack preview capabilities, making it hard to determine what exactly your changes have wrought.
However, the power that plug-ins bring to the GIMP is undeniable. From adding functionality to replacing existing features with alternative methods, GIMP's vast plug-in library should ensure a healthy future for the image editor.