This beginner’s tutorial describes how to make shadows pop in GIMP without that overly cheesy “HDR” look.

Open a photo in GIMP. In this example I’m using a plain ol’ JPEG.

Duplicate the layer and desaturate it.

Invert it.

Set blending mode to “Overlay”, strength 50.

Duplicate the base layer again, move it to the top and set blending mode to “Lighten only”.

A side-effect of this lame tone mapping technique is that high radius halos mighty appear, and the sky could be darkened in a cheesy way. You would more easily notice halos in what should be an even blue sky than in grass or rocks. As we only want to make the shadows pop and we don’t want a fake “HDR look” cheesy sky, we fix it in this step. This layer’s job is to undo the effects of this whole technique in the light areas.

Go back to the black-and-white layer and blur it. How much you blur it depends on how large your image is and on taste, that’s why I left this step for last. 30 works well in this example.



Done.

Desaturating in step 2 can be done in numerous ways:

You could just desaturate it as I did, but there already you have 4 methods to choose from (in GIMP 2.9.4).

You could use the Mono Mixer, enabling “Preserve luminosity” and sliding the “Red Channel Multiplier” all the way to the right.

You could decompose the image to RGB (or other) and use one of the resulting layers.

Note: Decomposing to RGB and using the R channel leads to an almost identical result as you’d get using the Mono Mixer as described in the previous step - a workaround if you’re stuck with GIMP 2.8.

Compare the first and last screenshots. The end result is a photo with a little bit more pop without looking fake. Lower the blur radius and try other desaturation methods for more cheese.