Pietro Lorenzetti is strongly light-biased - shadow is suggested rather than declared. Pietro Lorenzetti builds on cool foundations: the palette favours the blue-cyan-green arc. Chroma is kept low across all colours, producing the soft, enveloping quality that characterises tonal painting. Pietro Lorenzetti gives 60.6% of the composition to a single #BFBDC0 - a decisive chromatic anchor. The saturated accent, #864346, registers at 1.3% - sparse enough to feel like a deliberate surprise. At 62 units of value range, the palette has the tonal breadth to sustain complex spatial readings. High luminosity and cool temperature suggest the plein-air condition: unfiltered daylight and open sky. In the context of Pietro Lorenzetti's full range of palettes, group 4 represents one movement in an ongoing chromatic dialogue.