Solidité des couleurs et régularité des bains : contrôler les nuances

Two complaints damage apparel brands more than almost any other: “the color does not match the photo” and “it faded after a few washes.” Both trace back to the same discipline — color control in dyeing and finishing. For knitwear, where fabrics are dyed in batches and garments often mix components from different lots, controlling color is a genuine technical challenge.

This guide explains dye lot variation and color fastness, and how buyers can specify and verify both.

Two Different Problems: Shade Drift and Fading

It helps to separate the issues clearly.

They have different causes and different controls. Buyers should specify and test for both.

What Causes Dye Lot Variation

Dyeing is chemistry applied to a moving target. Even with the same recipe, batches can drift because of:

Because these variables are always present, the goal is not perfection but control within an agreed tolerance.

How Shade Is Measured: Color Difference and Delta-E

Color matching is not purely subjective. Modern dye houses measure shade difference with a spectrophotometer and express it as a **Delta-E (dE) value** — a numerical measure of how far one sample is from the standard.

Visual assessment under standard lighting (such as D65) still matters, because two samples can have the same dE yet look different to the eye. Use both instrument and visual checks.

Color Fastness: The Four Tests That Matter

Color fastness is measured against international standards, most commonly the ISO 105 series. Four tests cover the failure modes that affect knitwear most:

Wash Fastness (ISO 105-C06)

Simulates domestic washing. Evaluated for both color change (the garment fading) and staining (color transferring to adjacent fabric). This is the test most relevant to everyday apparel.

Rub / Crock Fastness (ISO 105-X12)

Measures color transfer when fabric is rubbed, both dry and wet. Wet rub fastness is typically weaker and is the one that fails on poorly dyed dark shades. Relevant to garments worn against skin or other fabrics.

Light Fastness (ISO 105-B02)

Measures fading under light exposure, rated on the blue wool scale. Important for products displayed or worn outdoors, and for display garments.

Perspiration Fastness (ISO 105-E04)

Measures color change and staining under artificial perspiration. Relevant to close-fitting garments and items worn against skin in warm conditions.

Why Dark and Saturated Shades Are Harder

Deep blacks, navies, bright reds and saturated jewel tones are the hardest to dye consistently and the most prone to fastness problems. The more dye loading required, the more likely that some dye remains on the surface rather than fully bonded to the fiber — which is exactly what rubs off or fades.

For these shades in particular, insist on test reports rather than assuming.

How Buyers Can Control Color Across a Program

1. Approve a physical color standard

Do not approve color from a screen. Approve a physical swatch or lab dip, and keep a retained sample. Pantone TCX references help, but the physical standard is the reference.

2. Specify Delta-E tolerance

State an acceptable Delta-E and the lighting condition for assessment. This turns a subjective disagreement into a measurable one.

3. Keep components in the same dye lot

For a single style, the body, rib, cuffs and trims should come from the same dye lot wherever possible. Mixing lots is the most common cause of visible mismatch within one garment.

4. Order dyed-to-match together

Rib and trims should be dyed to match the body, not dyed separately to an approximate shade. Coordinate this in the purchase order.

5. Require test reports per colorway

Ask for wash, rub, light and perspiration fastness reports for each color, especially darks and brights. Verify the report’s date, product and issuing lab.

6. Manage reorders deliberately

A reorder produced months later may not match the original exactly. Ask for the retained standard to be used, and request a pre-production sample before committing to a reorder.

Red Flags to Watch For

Conclusion

Color is one of the most visible quality signals your customers perceive, and one of the hardest to control in knit production. Separate shade drift from fading, specify Delta-E tolerance and approved physical standards, keep components in the same dye lot, and require fastness test reports per colorway. Control these and you prevent two of the most damaging complaints in apparel.

Key Takeaways for Buyers

Work with HONGTEX

HONGTEX is a vertically integrated knit textile manufacturer based in China, offering in-house knitting, dyeing, cutting, and finishing under one roof. From fabric development and sampling to bulk production and third-party quality inspection, we support brands, retailers, and trading companies across every step of the product journey. Contact our team today to discuss your project and receive a tailored quotation within 24 hours.