Usually I'll do a color study before diving into a big painting. The main reason is to map out the overall visual impact I'll be going for, which is difficult to do on the actual final canvas when I'm in the weeds painting. The color study allows me to push and pull the hierarchies of values and since it's at such a small scale (usually 8 x 10 inches), I'm able to work the whole of the little canvas quickly and manipulate the drama of the painting over and over as I need.
This time, with my 90 x 60 inch painting of the golems which Vin Ganapathy inspired (26 heads), I did so many compositional studies before transferring that I was so anxious just to begin. Now that the painting is underway (I won't post until it's a bit more further along), I realized I actually did need to step back and do that color study, in particular to figure out how to resolve the background. Shortcuts never do seem to work out for me after all:) Anyway, it was a nice breather from the big 'un.