This was just a fast pass using Wavelet Decompose (5 levels) and matching tones.
Wavelet Decompose image (5 levels)
Duplicated residual layer.
Adjust curves to match lighter part of arm skin tone with the upper.
Add layer mask, paint in lower arm.
This was a rough pass, so I’m sure it could be masked better. I also adjusted the opacity a bit (could be modified further and dialed in as needed). Just adjust the painted mask to blend the regions a little better, and the opacity to adjust the strength of the result.
Wow, thanks for all the great tips! I definitely have much to learn – still haven’t found time to try photoflow (does look interesting), though I’ve used wavelet decompose for other things (following patdavid’s great tutorials).
@Unhammer Ehh, whatever gets the job done. I’m guilty of it myself. However, in most instances, it really is far easier to lay down too much color and then mask it out after the fact. Glad it was helpful.
I hope you guys don’t mind that I’m bringing back that old thread.
But it matches perfectly my issue on a current photo of mine and I’m searching for advices.
The starting point are harsh shadows on a subject that I’d like to remove or at least reduce as best as possible. Im working on GIMP in version 2.10.18
So far I made some progress by performing a Wavelet Decompose with 7 scales and evening out the hard edges on the last 3 scale layers under the residual layer.
That helped to get a smoother transition between the dark and the brighter areas.
Next i wanted to work (up)on the residual layer (I’m using a transparent layer over the residual) with a soft brush altering between LCh color and LCH Lightness Mode to even out the tonal transition. And this is the point where I’m having issues to get a smooth transition. So far the results are not very pleasing.
Thank you @s7habo for taking the time and creating a screen record of your proposal. As usual your contributions are really helpful.
The result is actually pretty convincing for my purposes and the “Blend Blur Brush” is probably the tool i was looking for. However while trying to reproduce the steps i was struckling in the usage of the Blend Blur Brush and while I believe my issues are mostly caused due to my inexperience in GIMP i was wondering if there is any setting that I might have overlooked.
In your video the very first 3-4 brush strokes on the residual layer cause a significant better transition while in my attempts the same brush strokes (at least I believe so) create some kind of blur but not really the same transition and after a few brush strokes more the transition area becomes visibly “peachy”. Kinda difficult to explain. I should consider making a screen record as well. But maybe anyone got a hint.
Got to practice more in the meantime.
Starting at 1:16 you can see that I converted the image from 8 bit integer (perceptual) to 32 bit floating point (linear light).
8 bit is not good for fine transitions, because the gradations can be very expressive. At the end of the processing I converted it back to the original 8 bit jpg image.
The settings of brush itself. I used a MyPaint brush that is good for mixing the colors. Have a look at the exact settings I used.
Yes, maybe this is a good idea. Then we can see what you’ve done.
Gave it a try and it’s working way better now.
Thank you so much @s7habo.
If you like to showcase the procedure on your Youtube Channel, I’d be glad to provide you the full portrait. Feel free to contact me. I’m certain, this is gonna be helpful for a lot of people out there.
There are also countless other possibilities (color balance, curves, levels, color temperature etc.)
You have to know exactly what you want to achieve. I need to know what would be a good skin color for you to know what is best to use.
I agree that channel Mixer is probably helpful to bring back some overall reddish tengue to the skin.
However i feel that due to the tone evening the slightest imperfections of the skin do not become visible anymore even though the structure is still there.
For example in the upper part of the arm you can see a red dot. While this is probably something I’d remove, I’d like to preserve the red on the smaller pores and imperfections that make the skin look natural. That is probably what i would call a good skin.
Currently experimenting with a combination of Channel Mixer and a Mask created by desaturating the base layer with Mono Mixer by pushing reds to maximum and greens and blue to a value so that only the pores of the skin remain.
Not convinced yet but probably a solution…
Maybe you should show the whole photo so that it is easier to see the difficulties you are facing. In my opinion, the cut-out of the Photo with the hand is too blurred to be able to see fine details of the skin.
Moreover, the logic of the lighting has been broken by smearing the transition at the hand (this can be seen in the clothing, which shows sharp separation between light and dark), which can also lead to a distorted impression.
Maybe you should just even out the color between these two areas and leave the differences in brightness as they are with a sharp border and coarse details of the skin.
(now to stop using that eraser myself 
)
