Look a little closer
Two nearly identical samples may come from different sources or represent a changed finish. If they lose their labels, an informal comparison becomes difficult to repeat. A design notebook should keep the sample’s identity separate from the judgement you make about it.
A note for your design book
Record a source reference, acquisition date and project role for each sample. When a choice changes, add a dated note rather than silently rewriting the original decision. Keep supplier claims clearly attributed and avoid treating them as independently tested facts. This modest recordkeeping helps another reader understand why a particular material entered the design and what remains unknown about it.