01
Ask what the description refers to
An unfading designation concerns the slate's expected color behavior, not a guarantee that every piece is visually identical. The supplied selection can still have a range of surface appearance and tone. Ask the supplier to explain the exact product terminology and show material representative of the order.
02
Specify the acceptable range
Review multiple pieces and discuss how unusual variations will be handled. If the design requires a particularly consistent appearance, make that requirement explicit before purchase and ask whether the offered selection meets it. Keep the approved samples for comparison with deliveries. Avoid treating a general descriptive term as a substitute for a documented, project-specific material selection.