math foundation

Where can I find explanations of the various photoshop operations in terms of RGB math/operation?

E.g. increasing brightness is easy:
R=R+<brightness>
G=G+<brightness>
B=B+<brightness>

increasing contrast is
R=(R-127) x <contrast> + 127
ditto for G, B

Some operations involve two sets of RGB (from two different layers). E.g. I would like to see how the various blending mode is done. Again, some are more obvious than others. E.g. lighter:
R = max (R1, R2) where R is the blended result, R1 and R2 are from two different layers

There are several blending modes that I don’t understand and would be nice to know.

I suppose I could download the source code for GIMP and read it. But I’m hoping there is an easier way. A book would be nice. A web-based article is also good.

Where can I find explanations of the various photoshop operations in terms of RGB math/operation?

Where can I find explanations of the various photoshop operations in terms of RGB math/operation?

E.g. increasing brightness is easy:
R=R+<brightness>
G=G+<brightness>
B=B+<brightness>

increasing contrast is
R=(R-127) x <contrast> + 127
ditto for G, B

Some operations involve two sets of RGB (from two different layers). E.g. I would like to see how the various blending mode is done. Again, some are more obvious than others. E.g. lighter:
R = max (R1, R2) where R is the blended result, R1 and R2 are from two different layers

There are several blending modes that I don’t understand and would be nice to know.

I suppose I could download the source code for GIMP and read it. But I’m hoping there is an easier way. A book would be nice. A web-based article is also good.