The value structure of Pierre Jean Edmond Castan is mid-key: quiet, controlled, and cohesive. 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. #FFFFFF at 31.0% of the palette: an overwhelming presence that pulls all other colours into its gravitational field. At 12.0%, #65482D carries the palette's sharpest chromatic charge: an accent that earns its place precisely because it is withheld. From deepest dark to palest light, the palette traverses 64 units of the value scale - a span that creates natural depth. The mid-to-high key, cool bias, and moderate chroma point to outdoor observation - sky and diffused daylight as the dominant light source. This is palette 1 of Pierre Jean Edmond Castan's sequence - a single chapter in a chromatic story told across many works.