A nomenclature of colors for naturalists, and compendium of useful knowledge for ornithologists.

Ridgway proposed a simple classification system, doing away with many subjective and evocative names that were currently popular. The work illustrated 186 colors. Digital facsimile from the Biodiversity Heritage Library at this link.

In 1912 Ridgway greatly expanded the work under the title of Color standards and color nomenclature. "The work became a standard reference used by ornithologists for decades after Ridgway's death, as well as specialists in such wide-ranging fields as mycology, philately, and food coloring.The book named 1,115 colors, illustrated with painted samples reproduced on 53 plates. Special care was taken to ensure consistency of color reproduction across the edition, as well as the prevention of fading. The color samples were printed as large sheets by A. Hoen & Co., cut into swatches one inch by one-and-one-half inches, and pasted into each bound book" (Wikipedia article on Robert Ridgway accessed 9-2017). Digital facsimile of the 1912 work from the Biodiversity Heritage Library at this link.