Donald Duck ...RPM motor oil

23.5" diameter sign printed on heavy gauge galvanized steel ... a specific steel that was created to accept this type of printing ink at the time (1940). Created for the marketing of Standard Oil Company of California's RPM motor oil. According to one source it was used on the back of taxi cabs during the winter-spring season. Down at the bottom directly at "6:00 o'clock" is the familiar "notch" in the sign in which marketing signs would be placed into a frame that would force the sign to be straight and even. Then the whole frame would be placed on the back of a taxi. The image was also used on covers for spare tires on commercial vehicles. - AMAZINGLY due to their size i kept Donald and the companion Mickey in a box for over thirty two years after finding them in their original boxes in the "Serendipity" shop in San Francisco. There were four of each but i only bought the best two of each, selling one Donald and one Mickey.The next summer i came back to get the other four but of course someone else accidentally had found a pleasant surprise.
UPDATE: I was lucky to get an original photo showing a sign mounted on the back of a taxi. ALSO beware of what appears to be several PHONY signs being sold on E-BAY (2018-26). Any painting can now be reproduced on canvas, metal , or porcelain with great results.