In 1920, scientists at Dupont's Redpath laboratory conducting an experiment, researching for a nitrocellulose pencil lacquer, by accident discovered a substance capable of retaining an unusually intense amount of pigment. Spurred by the interest of Charles Kettering, and with the assistance of his engineers at General Motors, this led to the development of a new, quick drying, colorful automotive lacquer, named Duco, which revolutionized car finishing. It was first used on a new GM car, the 1924 model of the “True Blue” Oakland. Thus ended the reign of black as the only practical, durable colour available for cars, iconic on the model-T Fords. Within two more years, all General Motors cars were offered in a choice of colours. DuPont's purchased a 23 percent stock interest in GM in 1917-1919.«Image: the “Acid Test,” an inset from the cover of a 1924 Oakland Duco Finish pamphlet.