Canning novelty. Early methods of manufacture employed poisonous lead solder for sealing the cans. Studies in the 1980s attributed the lead from the cans as a factor in the disastrous outcome of the 1845 Franklin expedition to chart and navigate the Northwest Passage. Later studies found this to be false. Increasing mechanization of the canning process, coupled with a huge increase in urban populations across Europe, resulted in a rising demand for canned food. A number of inventions and improvements followed, and by the 1860s smaller machine-made steel cans were possible, and the time to cook food in sealed cans had
Campbell's Soup Cans Although Warhol had produced silkscreens of comic strips and of other pop art subjects, he supposedly relegated himself to soup cans as a subject at the time to avoid competing with the more finished style of comics by Roy Lichtenstein. He once said "I've got to do something that really will have a lot of impact that will be different enough from Lichtenstein and James Rosenquist, that will be very personal, that won't look like I'm doing exactly what they're doing." In February 1962, Lichtenstein displayed at a sold-out exhibition of cartoon pictures at Leo Castelli's eponymous Leo Castelli Gallery,