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 which is then transferred with glue onto silk. In either case, one needs to produce a glue-based version of a positive two-dimensional image (positive means that open spaces are left where the paint will appear). Usually, the ink is rolled across the medium so that it passes through the silk and not the glue. Campbell's Soup cans were among Warhol's first silkscreen productions; the first were U.S. dollar bills. The pieces were made from stencils; one for each color. Warhol did not begin to convert photographs to silkscreens until after the original series of Campbell's Soup cans had been produced.