Art Nouveau works in the upper reaches of the value scale, creating an atmosphere of brightness and expansiveness. Cool tones set the register here - the blues and greens easily outweigh any warm accents. Chroma is kept low across all colours, producing the soft, enveloping quality that characterises tonal painting. The saturated accent, #CAA542, registers at 2.7% - sparse enough to feel like a deliberate surprise. The full value range is 63 units: broad enough to build convincing three-dimensional form. High luminosity and cool temperature suggest the plein-air condition: unfiltered daylight and open sky.