These reductions are not simply the swift economy of the drawing, in which mass is indicated without detail, but by the instant weight of water in copious brush-strokes, strokes which contain not only form but light and not just any light, but the precise time of day, if possible to the very half hour. The mass movement of tropical cloud is not slow, especially over open spaces, and sharply rising mountains, unlike temperate climates in which sky can settle for long stretches of time, and in which, apart from truly intense summers, the atmosphere is already damp, providing its own basic washes, usually of a hue that infiltrates everything.