Historically, wallpaper was treated with toxic pigments containing arsenic, lead, and antimony. After 1775, a particularly dangerous substance known as copper arsenite was commonly used, developed by the chemist Karl Scheele. This pigment gained immense popularity and became known as Scheele's green, celebrated for its vivid color.

As time went on, Scheele's green was enhanced with copper acetate, producing an even more vibrant color called emerald green. This appealing shade found its way into a variety of products, including playing cards, candles, clothing, and even food, although it was especially favored for wallpaper.