Color-blindness : its dangers and its detection
A medical treatise on colour blindness published in London and Boston in 1879 by the physician Jeffries B. Joy, aimed at doctors and professional readers concerned with detecting defective colour vision. Its pictures are plain diagrams: a row of numbered colour swatches, a spectrum-like curve chart labelled with letters and figures, and a small shield-shaped ornament, offering a designer clean reference for simple charts and tidy numbered key layouts.
