A visible surface condition that departs from the specified appearance of glass or a coating under a defined inspection method.
GlassRenu · Educational illustration
Meaning and boundaries
Blemish is an appearance term, not automatically damage, nonconformance, structural risk, or a restoration requirement.
Why it matters in glass restoration
The term allows observation to be recorded before cause, acceptance, and repairability are determined separately.
Related terms
References
- ASTM International — ASTM C1036-25: Standard Specification for Flat Glass
Publisher’s original source - ASTM International — ASTM C1376-21a: Pyrolytic and Vacuum Deposition Coatings on Flat Glass
Publisher’s original source - National Glass Association — GANA Glazing Manual, 2022 edition
Publisher’s original source - National Glass Association — Guidelines on How to View Decorative Glazing Products
Publisher’s original source