The brand’s signature dark-green pack was changed to white in 1942. In a famous advertising campaign that used the slogan “Lucky Strike Green has gone to war”, the company claimed the change was made because the copper used in the green color was needed for World War II. American Tobacco actually used chromium to produce the green ink, and copper to produce the gold-colored trim. A limited supply of each was available, and substitute materials made the package look drab.