A technique I just found almost by accident, to gives results very similal to the “freaky details” processing:
Vivid light (other * light also work with slightly different results: Linear light, Hard light
Filters>Enhance>High pass and play with the settings since the enhancement is done in real-time (you can decrease contrast a bit from the default).Before:
After:
Well, quick testing if flat light blending mode (Exist only in Krita 4.2 or something to do with MATLAB which is where I found the formula for it) works better here. It’s like vivid light, but the difference is that flatlight doesn’t go under 0 or 1, and it’s a spreadout version of vividlight. Vivid Light does go over 1 or under 0 range.
In Krita 4.2
Alternatively,
Duplicate > Wavelet Decompose
Use one of the scale as flatlight blending layer. Could duplicate twice if you wish. Here’s the alternative result
Nice shot and a nice trick with the highpass filter and the blending mode. Good for increasing local contrast. Could reproduce that with Darktable.
In your image I applied it around the eyes to highlight them. I actually blurred the image around the eyes a bit and added some vignetting to decrease the presence of the background.
Then I gave the orange fur a bit more saturation and reduced it in the green background.
I liked the above image, so I did another attempt with Krita 4.2.
Similar idea to the above
Layer structure since I can’t share .KRA file here
And a little help from G’MIC in the final step.
I’m glad I put “simplified” in the thread title 
Simplifying while retaining the freaking details isn’t so simple.
— when I was a student
I ended up working on High Pass filter for Krita 4.2 because of this thread. Should be almost ready after I find out how to fix a little problem.
