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 escape Lichtenstein's lengthening shadow. Although his soup cans were not as shocking and vulgar as some of his other early pop art, they still offended the art world's sensibilities that had developed so as to partake in the intimate emotions of artistic expression. Contrasting against Caravaggio's sensual baskets of fruit, Chardin's plush peaches, or Cézanne's vibrant arrangements of apples, the mundane "Campbell's Soup Cans" gave the art world a chill. Furthermore, the idea of isolating eminently recognizable pop culture items was ridiculous enough to the art world that both the merits and ethics of the work were perfectly reasonable debate