The principles of beauty in colouring systematized
A colour theory treatise by David Ramsay Hay, published in Edinburgh and London by Blackwood in 1849, written for artists and designers studying colour harmony. The pictures are hand-coloured hexagonal colour wheels with six numbered triangular segments around a central star of letter-labelled hexagons, with handwritten annotations in the margins, showing how primary and secondary hues are arranged to produce harmonious pairings a designer could adapt into palettes.
