Mid-key values give Jacoba van Heemskerck its characteristic quietness - nothing blazes, nothing disappears. Jacoba van Heemskerck 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. The highest-chroma note - #AC331D - appears at just 3.3%, deployed as a precision accent against the quieter ground. A value spread of 63 units gives the palette both depth and air - shadows are genuinely dark, lights genuinely light. High luminosity and cool temperature suggest the plein-air condition: unfiltered daylight and open sky. Jacoba van Heemskerck arrived at this balance through long practice; the palette carries the weight of that experience.