Exercise 1

I took a deliberately bad picture of the mighty Nola cat in the 6:00 AM light. I had the white tile to let me color balance, so this was an attempt to see how I could do using GIMP, benchmarked by the Olympus automatic processing.

I used a technique for removing a color cast, where I find three parts of the image that are white (paw, floor, shadow on floor) that have different amounts of light. White should be equal red, green and blue, so I raised the blue and lowered the red to match the green on each spot using a curve.

Here's the original RAW file (as JPEG but with no cleanup)

 My fix (using GIMP, normalizing RGB on three points)...

Olympus wins this round. I think it cheated, but I can learn from cheaters.

When you get down to it, though, the color on my edit is more true, but I haven't brought up the contrast or brightened the colors. It makes me think that if I can add a few other tricks to the bag that I'll be able to rock the digital darkroom.

Full credit to the lesson I found at Grokking the GIMP