Light directed at a shallow angle across a surface so small height, texture, gloss, and scratch differences cast highlights or shadows.
GlassRenu · Educational illustration
Meaning and boundaries
Raking light is a diagnostic aid, not a universal pass-or-fail condition for installed glass.
Why it matters in glass restoration
It helps locate fine scratches, residue, pits, coating rub, and blended-area transitions before treatment.
Related terms
References
- U.S. National Park Service — Preservation Matters: Stained Glass
Publisher’s original source - U.S. General Services Administration — Cleaning Historic Masonry
Publisher’s original source - Getty Conservation Institute — Twentieth-Century Building Materials: History and Conservation
Publisher’s original source