Markus,
Gamma is basically a crude contrast bump although the exact effect of gamma you refer to would depend on which program you are referring to.
Not sure about programs like PI.
In Photoshop there are numerous ways to do it, each a little different in effect.
I like to keep all in my toolbox.
- a midtone selection mask using a blendif layer and layer blending
- LAHR filtering
- ACR (Lightroom or Photoshop) carefully using the clarity slider.
I am currently preparing a new photography workshop scheduled for July on (non-astro) photography.
INSERT SHAMELESS PLUG HERE
https://www.photoaccess.org.au/learn...-intermediate/
So I don't have time to write a tutorial. If you're coming to SPSP, catch me there during the day and I'll be happy to show you.
regards
Joe