Do you photograph your art as you are creating it to provide documentation of the process? I do. Perhaps obsessively I do. However, documentation shows the evolution of each work. I can see the changes as well as additions that take place to get to the finished piece.
I also create color charts at the start which are based on what I am seeing in my mind for the drawing. This helps me keep track of the specific colors that I am using. The color selection is not written in stone. I may use all or some or even add more along the way. I then have the color combo documented in case I choose to play with the same colors in another composition.
Oh yes, I also use PhotoShop near the end when the very last detail will either suffice or push the work into being overworked. This is where I am right now. This drawing is not finished. The final details can be the struggle.
Yellow (tsah-HOHV) 22″ x 30″, pastel-graphite on Fabriano paper.