RE: Crystal reflections: why a dark patch is not a coating test · RWI-01510

Summary draft for “Crystal reflections: why a dark patch is not a coating test”: the answer addresses “Compare multiple controlled angles and describe the visible observation without asserting…”; the related point is “No single lighting setup settles…”. Keep both connected to the opening question, and mark any conclusion needing further records as unresolved. Review focus: scope. Keep the stated question separate from any broader claim.