UV control.
Below 75 μW/lumen on sensitive works ; below 10 μW/lumen on paper.
UV accelerates pigment degradation, paper yellowing, textile fibre breakdown. Museum conservation protocols typically limit incident UV to below 75 μW/lumen on sensitive works, below 10 μW/lumen on paper. Envelope specification delivers this through spectrally selective coatings, laminated interlayers with UV-blocking PVB/SGP additives, and electrochromic or variable-tint glazing where natural-light fluctuation requires it.
