I have part of the picture that was drawn primarily using a certain linear gradient starting with white and ending with certain color, simplest example - think of a yellow ball on the black surface illuminated by a source of a white light. I also have other gradient available also starting with white and ending with some other color, e.g. think of a green color, now I want to change yellow ball to a green one. In my case I have a much more complicated shape intertwined with black lines and also including some gradients from black to the source color - think of the same yellow ball that someone decided to divide by "cells" using black lines.
I'm looking for a formula or any way to be able to do what I want in more efficient way than by just moving the bars in "Hue/Saturation" dialog.
Normally I do this via "Hue/Saturation" but I am apparently not proficient enough to use it as I'm not able to figure out positions of three bars that are available to at least remotely get the desired result when the source colors would be target to plausibly match the given gradient. I wonder if I can use a some sort of a formula to make it easier to myself to compute what bar positions in "Hue/Saturation" should be if a certain color in the selection must be changed to match some required one? If that's achievable via some other option, that'd be great to know too.
Hard to tell without seeing your picture but the first thing I try is usually
Color > Map > Rotate colors:
... because it can work beautifully, and is quite easy to try.