My G’MIC work flow. I am really bad with colours, so maybe my result is ugly. But my steps should be okay for someone with better eyes and judgement. I will say it in words that everyone can understand.
1 Find average colour of entire photo and make a copy (layer) filled with that colour but inverted.
2 Shift the RGB channels as desired. (You may want to do step #3 for preview purposes.)
3 Merge (down or to new layer) by multiplying original with copy (layer).
4 Cut (clip) highlights. I clipped and stretched the image but you should probably change the exposure. Do this to bring the skin and faces into the lower mid tones and remove contrast on the screen, which shouldn’t be the focus on the photo. It’s distracting!
5 Chroma adjustment. This will further deemphaize the screen and tame the colourful cardboard or fabric that is covering the edge of the stage, which is very distracting!
For this, decompose the image into L*C*ho and then do the following on the C channel: use the curve tool to clip the top highlights and pull down the mid tones and shadows. (You may not need to de- and re-compose if your editor has a tool that can handle the C channel with curves.)
6 Make grey scale copy (layer), give it a mask of itself and use that to blend with the colour layer below by opacity.
7 Take other steps for taste. I just sharpened the image a bit and resized it for the post.
Bonus my G’MIC command. This is a one-liner. It could probably be optimized and generalized into a new command if there is a demand for that.
– ^^
is an escaped ^
– afre_*
and *_
commands are my public and private commands, respectively.
gmic cc.jpg r,g,b={[${-average_colors}]^^-1} s c *[0] $r *[1] {$g*.8} *[2] {$b*.65} a c c 0,50% chroma_ .5,.8 +afre_y50 1 to_rgb. n 0,255 +l. n 0,1 f gauss(i-1) n 0,.4 endl blend_fade[0,1] . k[0] afre_sharpenfft 10,1 r2dx 1800,2 n 0,255 round o corrected-afre.jpg