This isn’t really a tutorial, just some ideas and how this particular take ended up with this given combination. Mostly because I lack the motivation to take a screenshot of every single step, and I highly doubt it would be useful enough to anyone to be worth the time.

So.

I’m assuming that you’ve procured a copy of GIMP, as used earlier. Step one for this particular image (grab the original here) is to correct the lens distortion that we’re getting. This is can be accomplished with the eponymous Lens Distortion tool, found in Filters → Distorts. As illustrated, this has uses other than inducing artificial fisheye – using a Main value of -7.7 and an X shift of -100 did a fairly good job of correcting the issue.

Step two: Curves. Good stuff. Raise the lights, dim the shadows. Boost the mid-range greens to bring out the fields a little more. Minor tweakage of reds/blues, nothing huge.

Three: the vignette trick from earlier (”vicarious vignetting“ apparently sounded like a good name at the time).

Four: Colors → Components → Decompose. Leave it at RGB, decomposing to layers, hit OK. This results in a new monochrome image with three layers, depicting the values of the three color components. You can often get better black/white image results by selecting one of these three layers (or mixing them together), rather than just going with a straight-up desaturation. But – not to get off track – copy the Red layer, paste it back over the original image. Hit the new-layer button to .. give it its own layer, then change the layer mode to Value. You can figure out what this does.

Five: duplicate the bottom image layer (the one with the actual picture), put the duplicate on top, change the mode to Saturation.

I’m not going into much detail here, apologies. Just throwing out some ideas.

(Tuesday’s coming.)