Why does printed colour sometimes look different between label batches?

Printed colour can look different between label batches due to variation in ink batches, press calibration drift over time, differences in the substrate used, or changes in printing conditions such as humidity, and this is more likely when colour was matched visually rather than to an objective standard like Pantone.

Ink itself can vary slightly from batch to batch depending on the ink manufacturer’s own production tolerances, and even small variations can become visible when printed at scale, particularly for large solid colour areas where any inconsistency is more noticeable than in fine detail or photographic imagery. Press calibration can also drift gradually over time through normal wear on plates, rollers, and other components, meaning a press that produced accurate colour on one run may need recalibration before producing an identical result on a repeat order months later.

Substrate changes are a less obvious but common cause: if a repeat order uses a slightly different paper stock, film thickness, or surface coating than the original run, even identical ink can appear to print a different shade, since the underlying material affects how ink sits and reflects light. Environmental conditions during printing, particularly humidity and temperature in the pressroom, can also subtly affect ink behaviour and drying. The most reliable safeguard against batch-to-batch colour drift is specifying colours against an objective standard such as Pantone rather than matching visually to a previous physical sample, and retaining an approved physical colour reference that future batches can be checked against.