So do you mark your contact sheets? With what medium? What color? Grease pencil/china marker? Crayon? Sharpie? Pencil? Or dont make a contact sheet? This intrigued me as I watched the Contacts Vol. 1-3 documentary series which I loved. Many of the great photographers marked them with all sorts of crazy colors, from whites to reds, to greens, etc. Some didnt make them, but almost all did. It was pretty awesome seeing a bit of their thinking preserved while marking them, a half mark there, a streak, an arrow, a partial box, and the final selected negative to print circled or boxed out with an abundant amount of lines and squiggles around them. I personally don't mark my contact sheets, as I dont make many, opting for a digital one since I scan as well as print, but I might soon. I found that a silver sharpie marker works great, and is highly visible in the darkroom, as well in plain light, but is not erasable. What do you use, and do you have a specific system of colors?