Undiffused sunlight falling directly on the glass or entering the observer's viewing path.
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Meaning and boundaries
Direct sunlight can reveal scratches, particles, coatings, or strain patterns but is excluded by some product appearance methods and can heat the glass.
Why it matters in glass restoration
It should be recorded as a diagnostic condition, not silently treated as universal acceptance lighting.
Related terms
References
- National Glass Association — Guidelines on How to View Decorative Glazing Products
Publisher’s original source - National Glass Association — Iridescence in Heat-Treated Architectural Glass
Publisher’s original source - National Glass Association — Proper Procedures for Cleaning Architectural Glass Products
Publisher’s original source - National Glass Association — Construction Site Protection and Maintenance of Architectural Glass
Publisher’s original source