Andrea del Castagno distributes its values across the middle register, creating harmony without high contrast. Cool tones set the register here - the blues and greens easily outweigh any warm accents. A restrained, mid-chroma palette: every hue is present and legible, but nothing shouts. The most saturated colour, #8B4E32, is reserved to 10.4% of the surface, where it acts as a focal punctuation. The value range spans 63 units across the palette, providing the full gamut from deep shadow to near-white and ensuring clear tonal hierarchy. The mid-to-high key, cool bias, and moderate chroma point to outdoor observation - sky and diffused daylight as the dominant light source. Andrea del Castagno's palette 4 carries its own internal logic while remaining in conversation with the artist's broader colour intelligence.