Test the new and enhanced Shadows/Highlights tool

(Andrew) #41

Interesting. I like the look of the fruit in the second image. (The two colour images are presumably before and after?)
The process is above my head but where did the three gammas 2 .8 .5 come from / how derived?
Is it easy to apply this processing to my test image above, the TIF? - I’d be interested to see the results.


Completely arbitrary gamma values just to demonstrate (higher = brighter, untouched = 1). That’s all I wanted to do here - show that gmic makes testing extremely fast compared to writing in c and compiling. I wouldn’t suggest this as a drop in replacement; it’s working in sRGB “gamma” and doesn’t allow radius selection amongst other issues. Nonetheless, here’s an example of the test image with quite aggressive values 2,1,0.5:

As you can see, there is some halo. That could be reduced by changing radius.

Edit: yes the previous was before (top) and after (bottom).


I would like to understand the problem better. What would the gradient ramps look like ideally?

(Andrew) #44

I’d suggest something like this -

  1. Before

  2. After

  3. After but with less tonal width

@garagecoder, thanks for posting your GMIC version.


I did an experiment. I get that too when I really push the the edges of the ramps. See how @garagecoder’s ramps have dark and bright edges? When I try to smooth them out perceptually, the artifacts appear. I won’t share the G’MIC code or images because they didn’t output correctly and I don’t have the time to figure it out.

(Bill Martz) #46

I looked for that build, but didn’t find it on 181025.