Before comparing a sample, record what you actually know about it: source, visible finish, date received, and the question you want the sample to answer. An unknown blank should remain unknown rather than being assigned a material identity from appearance alone.
Make one sample answer one question
For example, a note can ask whether a proposed layout is readable in a photo. That is different from a claim about compatibility, durability, or repeatability. Keep observations narrow and preserve the original label or supplier note where available.
If the sample needs more investigation, add a new question instead of stretching one image into a broad conclusion. More documentation habits are available in /updates/.