Chromolithograph Proofs with color and saturation options

United States: J.L. Hopkins & Co, 1915. Very good. Minor toning, dust soiling.. A set of four (4) chromolithographed printer's proofs offering different color and saturation options. Produced for the J.L. Hopkins & Co., a pharmaceutical firm that imported "all kinds of roots, barks, herbs, gums, leaves & seeds which are used for medicinal purposes". Each proof features an illustration of Earth with the continents labeled, with the tag-line "The Earth Contributes and J.L. Hopkins & Co. Distribute". Each proof offers a different combination of color and saturation, which the company was presumably asked by the printer to choose between. The company did use the logo, including a smaller pared-down version that was used in their advertisements for Cannabis Americana in 1917. Four bifolia measuring 8.25" by 5.75", chromolithographed on first pages. J.L. Hopkins & Co. was taken to court at least twice for adulteration or alteration of their products.