A material log works best when it has two columns: what you can see and what you still need to verify. For example, a photo may show a change in appearance, while the cause or repeatability remains open. This distinction prevents a sample note from becoming a material promise.
Keep the sample identity attached
Write down the blank description, source reference, date, and the artwork version used in the observation. If two blanks look similar, give each one a separate record. The goal is traceability for a maker's own review, not a claim that all examples will behave alike.
Review before comparing
Only compare samples when their viewing conditions are recorded. A simple note about lighting and camera angle can explain why two photos should not be treated as a direct result comparison. Keep project claims separate from personal test notes.
More sample-documentation ideas are available in /updates/.