Ive read alot out "buffering" but never could find a rough estimate of how much white is needed. Say you had a yellow or blue or whatver color where would you start with X amount of color to X amount of white. Also say you needed a darker blue (cobalt blue). So you take your white and add it to your blue to make it opaque, but now the blue is way to light in color. How would you go about darkening that color.