Interesting (at least to me) how the effect of sun and moisture can affect weathering. All three boards come from adjacent structures and made of the same wood (aspen). The boards are warped so the bottoms get more sun than the tops. The granaries are in a row and the trees shade the buildings, but not equally.
Closest to the trees. Not monochrome (some flecks of yellow/red paint if you look closely) but deeply affected by the black mold that grows on rotting wood locally. Short exposure to direct sun and that mainly on the bottom
Farther from the trees than the first so less damp and more sun Filtered sunlight for most of the day.
Farthest from the tree shadows. Direct sunlight