I draw onto the surface of in-progress paintings with different colored grease crayons in order to guide me as I continue to work. Let me explain. My paintings originate from my own photos. I print out a photo, and, as I learned in drawing 101, I grid the photo into sections using different colored grease crayons. I then draw the image from the photo onto the in-progress painting. As I need to work on a flat surface, and am unable to step away from the painting as I would an oil painting, I rely on the crayon lay-out to tell me where to place different colored pulps.