"Schäffer's system relied on colors that could be found in an artist's shop, and it called for many mixtures, including combinations within a color group: reds with reds, browns with browns, etc. Rather than attempt to include all colors in a single sheet, he devised an initial page of principal colors, and separate pages for colors made from mixtures. Schäffer's conception of color is genealogical and hierarchical; he presented the principal colors not as a continuous line but as families, each with its own coat of arms." (from The Creation of Color in Eighteenth-Century Europe , by Sarah Lowengaard)