"In 1892, Cincinnati printer John Earhart, published The Color Printer: A Treatise on the Use of Colors in Typographic Printing, in which he detailed his methods for creating hundreds of color mixtures and thousands of color combinations as well as advice for complementary colors, using harmonious colors, and printing."
The Color Printer site is a digital edition of Earhart’s work created by Nicholas Rougeux with enhanced reproductions.
The Color Printer
Digital edition of John Earhart’s 1892 treatise on using colors in typographic printing
