Traité d'esthétique visuelle transcendantale : fondé sur la fixation des grandes lois des trois hypostases de l'objectivité visuelle, scientifiquement ramenées à une unité : à la première forme
A French treatise on transcendental visual aesthetics by Léon Arnoult, published in Paris by Charles Mendel in 1897, setting out laws of visual perception and colour theory for a scholarly readership. The four pictures are scientific diagrams: a schematic eye-like curve beside a grid of parallel lines, oscilloscope-style traces on black fields, and a labelled solar spectrum drawn as a graph alongside a gradient bar. A designer might borrow the clean line-based charts and the spectral gradient as models for showing colour sensitivity and wave response.
