John Martin is low-key throughout, a quality associated with Obsidian Pewter - deep shadows dominate the composition. John Martin tilts toward cool - blues and silver-greys carry the structural weight. Every colour is desaturated; the palette proceeds through near-neutrals and gently-coloured greys. The most saturated colour, #342D1B, is reserved to 8.3% of the surface, where it acts as a focal punctuation. From deepest dark to palest light, the palette traverses 55 units of the value scale - a span that creates natural depth. This tonal restraint is characteristic of the John Martin approach: colour serves light, not the reverse. In the context of John Martin's full range of palettes, group 7 represents one movement in an ongoing chromatic dialogue.