An introduction to the study of colour vision
A Cambridge University Press textbook of 1915 by the British physicist John Herbert Parsons, written as an introduction to the study of colour vision for students and researchers. Its pictures are plain scientific line graphs of spectral sensitivity curves, plotting relative brightness against wavelength in nanometres, drawn in black ink on ruled grids. A designer could take from them the clean, restrained language of technical charts: fine hairlines, labelled spectral axes, and overlapping curves in varied dash patterns.
