I took a two day workshop "The Thrill of Two-Sided Drafting Film" presented by Pam Belcher out of Seattle. I know it sounds like a dry subject but the potential of what it can do really is exciting. This was done on Dura-Lar matt film.
I cut a sheet of film to ATC size so each piece costs me a mere 5 cents to experiment on to learn how many layers I could or couldn't put on it, adding textures, how intense I could make the images, the speed a drawing could be developed, scannability, etc. The tag marked "F" is just there to tell me which side is the front and another to show which is the back side. To develop the intensity of color and detail both sides are used. Each side is different yet similar. At first I thought working two sides of anything would take longer but amazingly the technique is faster than traditional paper and the colors pop with little effort. Lots of potential here.