The documentary The Number on Great-Grandpa’s Arm uses a blend of interviews, historical film footage, original artwork, and rotoscope animation.

Rotoscope animation is named after the Rotoscope machine created by Max and Dave Fleischer in 1917. The machine allows film images to be projected frame by frame, letting animators trace those images to incorporate into their artwork. Some of the earliest well-known examples of rotoscope animation include Disney films like Snow White & the Seven Dwarfs, Fantasia, and CinderellaSometimes, as in the film Who Framed Roger Rabbit, animators use rotoscoping to add animated characters into live action footage.

In the video below, Jeff Scher takes us into his studio and shows us his artistic decisions and process in the rotoscope animation he created for The Number on Great-Grandpa’s Arm.