Henri Martin sits in the centre of the value range, lending the palette a sense of even, sustained light. Temperature is cool-dominant, with blue and green families claiming the largest areas. Chroma hovers near zero; colour declares itself through subtle shifts in hue rather than outright saturation. The saturated accent, #7F4C4A, registers at 8.0% - sparse enough to feel like a deliberate surprise. The palette spans 44 value units: a measured range that delivers coherence over drama. High luminosity and cool temperature suggest the plein-air condition: unfiltered daylight and open sky. Palette 18 sits within the larger chromatic argument that Henri Martin's complete body of work advances.