 Thick celluloid panels are cooked in a bain-marie which turns them into a leather-like substance.Panels are then turned on a mold and allowed to harden for as long as three months.A typical formulation of celluloid might contain 70 to 80 parts nitrocellulose, nitrated to 11% nitrogen, 30 parts camphor, 0 to 14 parts dye, 1 to 5 parts ethyl alcohol, plus stabilizers and other agents to increase stability and reduce flammability.