spill suppression

[Guillaume Charron]

I meant: “Can we do that in after effects?”

[Filip Vandueren]

In after effects expressions calculate the values of properties that can be keyframed. Not the RGB values of pixels.

What your expression seems to do (green values may never be more than the average of red and blue) could also be done like this:

Duplicate the layer,
on the top one, add a channel mixer and change the green sliders to 50%red, 0%green, 50%blue.
set the top-layer’s transfermode to darken.
If the layer had an alpha, enable “preserve Transparancy”

If you want to do it with just 1 1ayer you need “CC composite”, to darken the original back on the filtered output.

[Guillaume Charron]

thanks… I try that little trick. 🙂