Values in Thomas Birch rest in the mid-range - neither dramatically lit nor steeped in shadow. Thomas Birch tilts toward cool - blues and silver-greys carry the structural weight. Chroma is kept low across all colours, producing the soft, enveloping quality that characterises tonal painting. At 2.7%, #D6C69A carries the palette's sharpest chromatic charge: an accent that earns its place precisely because it is withheld. The palette spans 52 value units: a measured range that delivers coherence over drama. The mid-to-high key, cool bias, and moderate chroma point to outdoor observation - sky and diffused daylight as the dominant light source. Palette 4 sits within the larger chromatic argument that Thomas Birch's complete body of work advances.