The ruby slippers in The Wizard of Oz and the glowing forests of The Adventures of Robin Hood look like pure movie magic, but they were the product of a decades-long engineering fight against chemistry and light. This deep dive traces Technicolor from its origins with three MIT-connected engineers hired in 1914 to fix projector flicker, through the failed additive Process One, whose two-aperture projectors required a projectionist to keep red and green frames aligned by hand, and Process Two, which cemented two half-thickness films back to back only to have them warp and pop out of focus under hot projector lamps.

The episode explains the breakthrough of dye imbibition in Process Three, with skip-frame printing, gelatin matrices that acted like rubber stamps, and a mordant made from deacetylated chitin from crab shells to keep dyes from ble ...