A new elucidation of colours, original, prismatic, and material : showing their concordance in three primitives, yellow, red, and blue, and the means of producing, measuring, and mixing them : with some observations on the accuracy of Sir Isaac Newton
A colour-theory treatise by naturalist and illustrator James Sowerby, printed in London in 1809 to argue for yellow, red and blue as primaries and to correct Newton's account, aimed at painters and natural philosophers. Plates pair hand-washed watercolour charts—stepped bands, interlocking triangles, graded ternary strips—with stark black-and-white stair diagrams useful as geometric colour scales and hard-edged abstract patterns.
