Even if the rule in the major animation studioes since the 90's has been that 2D animation is colored by using digital ink and pint, meaning they stopped using tradtional cels about ten years ago (plus minus some years), it is said that Bill Plympton for this movie actually used the old cels and painted them by hand. Is this correct?
Bill Plympton did all the pencil drawing for "Hair High" by hand. The drawings were then photocopied onto cels, and a team of young artists (some students from the nearby School of Visual Arts) then did the cel-painting. This was done in 2002-2003.
Since then, Bill has used a new technique for his short films - he still does the drawing, but the pencil drawings are being scanned into a computer and colored digitally by other people. This will be the process for his new feature, "Idiots and Angels".
Bill will continue to do all the drawing by hand - for proof, he has a web-cam broadcasting from his drawing board to his web-site: www.plymptoons.com