A dark area appears at an oblique angle in a single photograph. Does that establish a coating difference?
| Field | Scope |
|---|---|
| Subject | Crystal reflections: why a dark patch is not a coating test |
| Exercise | Discuss the stated question; distinguish sources, interpretations and unresolved points. |
No single lighting setup settles that question. Compare multiple controlled angles and describe the visible observation without asserting material specifications that have not been verified.
Clarification for “Crystal reflections: why a dark patch is not a coating test”: the point beginning “No single lighting setup settles…” belongs to the question as written. It should not be read as a report that a new check, purchase or experiment has been completed. Review focus: scope. Keep the stated question separate from any broader claim.