A lining that crocks onto a white shirt is a chemical problem, not a “dark colour” problem. Colour fastness is the resistance of that dye to rub, wash, sweat, light and solvent. Linings fail in perspiration and wet crock more often than in a showroom. Spec the tests.
TrimGem asks for lining fastness on the same shade band as the shell, and tighter on pale garments.
Dye system follows fibre
- Polyester (190T/210T taffeta): disperse dyes, typically high-temperature (~130 °C) exhaust. Watch sublimation (heat migration in pressing) and unfixed dye (crock). Reduction clear matters.
- Acetate and polyamide: acid dyes, controlled pH (about 4–7), levelling and fixation.
- Cupro, viscose, silk: cellulose or protein systems as appropriate; lot-to-lot shade on regenerated cellulose is a classic complaint. Shrink and wet-crock travel together.
Do not dye a polyester lining in an acetate recipe and hope.
The tests
- Crock — dry and wet, standard cloth, grey scale for staining (GB/T 3920, AATCC 8, JIS L 0849).
- Wash — stated temperature and detergent (GB/T 3921, ISO 105-C06, AATCC 61).
- Perspiration — acid and alkaline (GB/T 3922, ISO 105-E04). Next-to-skin linings live here.
- Light — xenon (GB/T 8427, ISO 105-B02), 8-step blue wool; lining in a coat sees less sun than a shell, but a red jacket lining in a shop window does fade.
- Water (GB/T 5713).
- Dry-clean — if the care label is solvent.
- Hot press — sublimation on polyester.
- Saliva — infant.
- Chlorine / seawater — swim and marine, rare on a suit lining.
Change vs staining are both reported. Crock on a smooth filament can be oddly worse dry (slip) than wet; still run both.
Grey scales and the room
ISO/AATCC/GB grey scales, 5 best to 1 worst, half-grades allowed. Light fastness uses the 8-step. Grade in a D65 cabinet, neutral surround, 45° geometry, adapted eyes. Write the minimum (e.g. crock dry 4, wet 3–4, wash 4, perspiration 4) on the PO.
Sublimation on polyester linings often needs 3–4 if the garment will be pressed.
Why lining crocks
Rough or printed faces dump colour. Unfixed dye on heavy shades. Softeners that lock or, conversely, that help dye move. A lining is a large stained area against a shirt: perspiration + crock is the pair to name.
Lot shade (ΔE, illuminant) belongs on bulk, not only a first dip. “Eco dyes” do not replace a fastness table. A mill that dyes 129 colours of 210T from one greige still has to prove each dark shade; navy and black are the classic crock failures, not the pastel card.
Bulk is where shade continuity breaks. Ask for a retain of the approved dip, a ΔE limit under a named illuminant (D65, sometimes also A or F11 for stores), and a ban on mixing dye lots inside one cut. If the lining is piece-dyed after weaving, unfixed disperse on polyester will show as a powdery crock that a home wash will move onto a shirt yoke. If it is yarn-dyed (rare on cheap taffeta, common on some stripes), the yarn lot is the colour lot.
Write fibre, dye class, tests, minima, illuminant. If the lining is darker than the shell, staining risk goes up — the matching note says keep lining no darker than the shell when you can. Fastness is how you survive when you cannot.