I am stuck on a blending problem that appears to have only started once I started blending without any color. I am painting a grey suit and using shades to capture the lighting realistically. For some reason, when I paint with a dark grey over a light grey, with say 20% opacity, with enough strokes, the color I am painting will match the color in the color picker. With the reverse situation (light to dark), the paint tool never quite blends to the color in the color picker, it is always a shade or two off. No matter how many times I stroke the area, it will not become the color I have chosen. It has me dumbfounded and is crippling my ability to make light and shadow and show depth.
I have tried googling and messing with every possible option, deselecting all, triple checking what layer I am in, but I cannot seem to find anyone else with this problem...