Use site-specific exposure notes rather than a compass label alone.
Observe the actual light
A north-facing location is not a complete exposure description. Nearby buildings, trees, reflected light and seasonal sun angles alter what reaches the surface. Record what you can observe and mark seasonal conditions you have not yet seen. An uncertain entry is better than a confident assumption copied from another elevation.
Choose paired viewpoints
Photograph two locations with similar material and finish history but visibly different shelter. Keep framing and camera processing consistent. The pair can help a supplier understand your concern; it cannot isolate sunlight as the only variable if rain, dirt and moisture also differ.
Plan the next observation
For a screen below a deciduous tree, add a note to compare leaf-on and leaf-off conditions. Use the journal to retain that question instead of predicting the future shade pattern. Changes to landscaping belong in the record because the exposure setting can change without any change to the wood itself.
- Note direct light and obstructions
- Record tree or roof changes
- Avoid a universal greying deadline
Evidence & scope
Surface weathering research (2020), not a forecast for a supplied board or a structural assessment.
Original planning guidance. References support their stated technical scope; examples and workflows do not establish product approval.