Fabric for a large order is usually dyed in several lots. Each lot is matched to the approved colour standard within a tolerance, but lots still differ slightly from each other. If different lots are cut for different sizes, or mixed within cartons, those small differences become visible when garments sit side by side. The factory is right that it is one colour; the problem is how the lots were managed.

Shade grouping before cutting

Ask the factory to sort fabric rolls into shade groups before cutting, often called shade banding or shade lotting. Each group contains rolls that match each other closely. Cut garments from one group where possible, and never mix groups within one garment, since panels from different lots on the same hoodie are the most visible fault.

Keep sizes in the same group

For styles where customers often buy several sizes together, such as team or uniform orders, cut all sizes of a colour from the same shade group. If that is not possible, keep each group's garments together in packing, and mark the group on the carton.

Check against the standard

Compare a bulk garment from each shade group with the approved colour standard in a light box under agreed light sources. Agree how close is acceptable with the dye house and the factory. Also check that shade stays stable after washing, by washing samples with a named procedure such as ISO 6330 and assessing colour change as in ISO 105-C06.

Inspection

In final inspection under ISO 2859-1, include shade variation within a garment and between garments in the same carton as defects. Ask the inspector to pull pieces from different sizes and compare them together.

For reorders

Reorders are always new dye lots, so they may differ from the first order. If continuity matters, agree a tighter tolerance and approve a lab dip against the original standard before dyeing.

Keep the approved standard and a sample from each shipped shade group, labelled, for future comparisons.

Dark colours such as black and navy, and bright colours, usually show lot differences most clearly. Focus the tightest controls on those shades rather than applying the same effort to every colour in the range.