Wash, rub (crock), light, and perspiration fastness failures each point to different mechanisms — a fix for one can make another worse if the diagnosis is wrong. A wash-fastness fix that increases surface dye deposition, for instance, often degrades rub fastness.
Fixation cut short — by time, temperature, or agent dosage — leaves dye loosely bound to the fiber, showing up first as wash and rub fastness failure.
Unfixed surface dye left on the fabric after dyeing transfers directly during washing or rubbing — a process-step failure, not a dye failure.
A dye class chosen for the wrong fiber type or end-use environment will underperform on fastness regardless of application quality — on cotton-blend fabrics specifically, a dye suited to the cotton portion alone can leave the synthetic portion under-fixed and wash-fastness weak.
Pigment printing and coating rely entirely on cure time and temperature for fastness — under-cured pigment fails wash and rub fastness even with correct formulation.
Under-dosing leaves dye unfixed; over-dosing can cause its own handle and fastness issues. The correct dosage is fiber- and dye-class-specific, not a fixed ratio.
The corrective action differs completely depending on whether the failure is chemical fixation, mechanical surface deposition, or process timing — treating all fastness failures as one problem is how a fix for wash fastness quietly breaks rub fastness.
Wash, rub, light, and perspiration fastness are tested and diagnosed separately — a report that just says "fastness failed" isn't enough to act on.
Before we look at the dye or fixing agent, we confirm the washing-off step actually removed unfixed surface dye — a frequently skipped check.
Colour fastness is the ability of a dyed or printed textile's colour to resist fading or bleeding when exposed to the conditions it will face in use — washing, light, rubbing, and perspiration are the most common. It's one of the core quality indicators for any dyed or printed fabric.
The most common are fastness to washing, light, rubbing (crocking), perspiration, water, and hot pressing. Each is tested separately because a fabric can pass one and fail another for entirely different reasons.
A grey scale is a set of standardised grey panels with increasing contrast, used to rate how much a fabric's colour changed or bled after a fastness test, by visually comparing the treated sample against the panels.
The blue scale is a set of eight standardised blue-dyed panels ranked by how well each resists fading in light. It's used specifically to rate light fastness, and the same method can also be adapted for washing and perspiration fastness.
