If you used Photoshop for a while, you know that it is slightly harsh on the colors. It blends them in an odd way, sometimes not quite like how traditional paint mixes. It is also difficult to achieve a nice color range without going over into extremes and overly saturated or contrasted look. Overall, it’s hard to avoid that strange ‘digital’ look.
So, how to avoid that and not have the piece look muddy? Also how to make colors seem rich without the piece looking like an unicorn barf? Short (biased) answer: Slowy layer colors in various Layer Modes to build your piece up. Almost like the old masters, right?
I’m absolutely certain there are other ways, but as someone with classical training in painting, this seems the closest to the real thing to me personally. Below I went over all the steps I do to achieve the painterly look and color range I want.
*The screenshots of color picker window and the green squares mark the color range I use in each step. Note, however, that the hue is NOT the one I used in the piece.
Sample 