10 Essential Art Supplies for the Traditional Animator

From Adrien-Luc Sanders, former About.com Guide

When you're ready with your cels, you'll need paints. Painting on slick cels is very difficult, and requires a thicker paint, usually; I use acrylics, but some people prefer oils. The trick is to paint on the back side of the transparency, the opposite side from the side the that the copier toner is on; that way there's no chance that the wet paint will smudge the copied lines.