the alpha control FX was my goto tool but....alas....it falls short. its not possible to manipulate its range sufficiently enough, i can't flip it for instance...
this is what i need it for:
in a single color-shadow-layer with lots of alpha variation i need to bring down the opacity of the darkest pixels.
idealy i have a brush and where ever i paint over my layer it will bring down the opacity of the darker pixels(with less opacity) to a lower level
while at the same time leave the lighter pixels (with more opacity) as they are
inverse alpha diff blendmode-how.png
when you look at row 4
You start with the image on the left.. the dark part are pixels with low opacity(= little see through) and the light part being pixels with high opacity (=more see through.)
all pixels have the same RGB value only Alpha channel differs.
i want a brush that reduces the opacity of the darker pixels but not further than a certain threshold.
so that no matter how often i pass with my brush the pixels will not be made any more transparent than a certain valu.
it is the inverse effect of Alpha-diff blend mode (row 3)
Alpha-diff will not add aditional opaqueness to a pixel as long as the opaqueness value of the brush is lower then that of the pixels on the canvas.
i want to remove opaqueness from the pixels on the canvas ...unless they are already under the level of opaqueness of the brush. in that case they should not be made lighter but stay as they are.