I've watched the mixing colors video a couple times. As you try each new mixture to achieve the next step, you frequently observe that the attempted step is too small or too big and repeatedly adjust until it is satisfactory. How is the correct step determined? What is it that lets you know that the step is too big or small? I assume that exactness is not required, but I don't feel I'll know if the step is too big or too small unless it's way off. And how many steps are there? Is it the same for each color group? Is just following a standard gray scale as a guide for the approximate value the idea? Thanks.