The value structure of Hans Heysen is mid-key: quiet, controlled, and cohesive. A distinctly cool atmosphere runs through this palette: sky, water, and mist given colour form. Chroma is kept low across all colours, producing the soft, enveloping quality that characterises tonal painting. At 9.0%, #88765B carries the palette's sharpest chromatic charge: an accent that earns its place precisely because it is withheld. Value range is moderate at 42 units - enough contrast for legibility, not so much as to fragment the tonal unity. High luminosity and cool temperature suggest the plein-air condition: unfiltered daylight and open sky. In the context of Hans Heysen's full range of palettes, group 4 represents one movement in an ongoing chromatic dialogue.