Up through Disney’s previous animated feature, Sleeping Beauty, each cell in a film had to be traced and copied by hand, often more than once, then inked and painted — and each movie used hundreds of thousands of cells. That got expensive: Sleeping Beauty cost $1 million more than it earned in its first release (and in 1959 that was serious money). For Dalmatians, animators used Xerox cameras to copy the drawings for cells, saving so much labor and expense that the studio used the technique for the next 30 years, even though Walt didn’t care for the look. – Smithsonian Magazine
