Picture retouching

Last month, the dutch-languaged C'T featured an article about retouching pictures with The Gimp, amongst others. Great timing, of course, since everyone goes on holiday during summer, right? Right.

It's amazing what you can do with The Gimp and a bit of basic knowledge. Take this picture, for example, which I took at this year's FOSDEM:

I kindof like it, but the colors are a bit blend. Too much of a red tint over everything. So, what we need to do, is change the curve:

Pardon my, eh, Dutch.

The trick is to remember that there are only so many colors which can be represented in a (JPEG) photo. The histogram on the background represents that; and by modifying the curve that is above the picture, you can effectively change the colorspace that is available for any peaks. If there's a lot of the darker blue in the picture, but less so in the lighter regions of the blue (as in this case), you just give the picture more space in the blue regions so that the blue that actually exists in the picture can be better represented. We do this by lowering the curve right before the peak, and by raising it afterwards, as the above screenshot shows. After doing so for red, green, and blue, this is the result:

Looks much better, right? Way more contrast, and the colors look much more natural. And that only took me like 10 seconds to do.

Do watch out, though -- it's easy to overshoot, resulting in an ugly picture; and you wouldn't necessarily want that. Also, if your camera has a RAW mode, you're going to be able to do a lot more of this kind of retouching with that than you would be using JPEG files. Then again, my camera has RAW too, but I don't use it most of the time...