Colorfastness: Test Methods, Standards and Grades

Colorfastness measures how well a fabric keeps its color under washing, light, rubbing, sweat and water. Each is a separate ISO 105 or AATCC test, graded 1 to 5 on the grey scale (light uses a 1 to 8 blue wool scale). Which tests a product needs depends on how it is worn and washed.

In Soo Seguier September 6, 2026 8 min

Colorfastness is where a good-looking sample turns into a returned garment. A fabric can pass every other check and still bleed in the first wash, rub off onto a car seat, or fade in a shop window. Colorfastness is the set of tests that predict that behavior before bulk production ships.

This guide covers what colorfastness is, how it is graded, the main ISO and AATCC tests, which ones your product actually needs, and where the check sits in textile manufacturing and quality control.

What is colorfastness?

Colorfastness is a fabric's resistance to losing or transferring its color when it is washed, exposed to light, rubbed, or brought into contact with sweat or water. Poor colorfastness shows up as fading, where the color changes, or as staining, where the color transfers onto something else, and each is measured separately.

That split matters because a dye can fail in two directions. Color change is the sample itself going duller or shifting hue. Staining is the sample bleeding onto an adjacent white fabric, a pale lining, or the next garment in the wash. A retailer cares about both, so a colorfastness result almost always reports the two as separate grades.

For a brand, colorfastness is a sourcing risk, not a lab curiosity. It is the difference between a dye that survives real use and one that generates complaints, returns, and, for children's products, safety recalls.

How colorfastness is graded

Most colorfastness tests are scored on the grey scale, a set of standard grey chip pairs, from 5 down to 1. Grade 5 means no change at all; grade 1 means severe change. The scale has nine steps in total, including the four half grades, written as 4-5, 3-4, 2-3 and 1-2.

Change in colour (ISO 105-A02): how much the tested sample itself faded or shifted, read against the grey scale for colour change.
Staining (ISO 105-A03): how much color transferred onto a white adjacent fabric, read against a separate grey scale for staining.
Light is the exception: light fastness uses the blue wool scale from 1 to 8, where 8 is the most resistant, because fading under light is gradual and needs a wider range.

Grading is usually visual, a trained inspector comparing the chips under standard lighting, though the change can also be measured instrumentally with a spectrophotometer under ISO 105-A05. Either way, the number on a report, such as 4 or 3-4, is a grey scale or blue wool grade, not a percentage.

The main colorfastness tests

Colorfastness is not one test but a family, each simulating a different way color gets attacked in real life. These are the ones that appear on most textile reports, with their ISO and AATCC references.

Washing (ISO 105-C06, AATCC 61): simulates domestic and commercial laundering with a reference detergent, and reports both color change and staining onto a multifiber strip. The most common test for apparel.
Rubbing or crocking (ISO 105-X12, AATCC 8): rubs a standard white cloth against the fabric, dry and then wet, to measure color rubbing off. Dark and wet almost always score worse than pale and dry.
Light (ISO 105-B02, AATCC 16.3): exposes the fabric to a xenon-arc lamp that mimics daylight (D65) and grades fading against the blue wool scale; ISO 105-B01 is the natural-daylight version. Critical for anything displayed, or worn outdoors.
Perspiration (ISO 105-E04, AATCC 15): tests the fabric in acidic and alkaline solutions containing histidine, the amino acid found in sweat. Essential for activewear and skin-contact garments.
Water and seawater (ISO 105-E01 and E02): color change and bleeding after contact with plain water and with salt water, relevant for anything worn in the rain or at the beach.
Chlorinated pool water (ISO 105-E03): for swimwear, tested at 50 or 100 mg per litre of active chlorine, and 20 mg per litre for beach accessories such as robes and towels.
Dry cleaning (ISO 105-D01) and saliva (DIN 53160): dry cleaning for tailored and delicate items; saliva and sweat testing is a safety requirement for babywear and children's products.

Which colorfastness tests does your product need?

You almost never run every test. The right panel depends on the fiber, the depth of the shade, and above all on how the product is worn and washed. The useful shortcut is to test for the stresses the garment will actually meet.

Denim and deep reactive dyes: prioritize rubbing (crocking) and washing; indigo and dark shades are the classic crocking failures.
Swimwear: chlorinated pool water, seawater and perspiration, plus light for the time spent poolside.
Activewear and sportswear: perspiration in both acidic and alkaline forms, washing and rubbing, because sweat and repeated laundering are the main attack.
Curtains, upholstery and outerwear: light fastness first, since sustained exposure is the dominant risk; a high blue wool grade matters far more here than for a t-shirt.
Babywear and children's products: saliva and perspiration are often legal requirements, alongside washing, because the garment ends up in a child's mouth.
White and pale linings: focus on the staining grade of everything they sit against, since their whole job is to not pick up color; spec this in the tech pack so the mill tests the right thing.

What counts as a passing grade?

There is no single universal pass mark; each retailer sets its own, but the working benchmarks are consistent. Most apparel programs want grade 4 or better for color change and 3-4 or better for staining, with light fastness expectations higher for anything displayed or worn outdoors.

Washing and water: color change usually 4 minimum, staining 3-4 minimum for apparel.
Rubbing: dry crocking around 4, wet crocking often relaxed to 3 or even 2-3 for dark and heavily dyed fabrics, where wet rub is genuinely hard to pass.
Light: roughly blue wool 4 for fashion apparel, rising to 5 or 6 for curtains, upholstery and outerwear that live in the sun.

Two honest caveats. Dark, saturated and pure shades are harder to pass, especially on wet rubbing, so a realistic spec sets the bar by shade depth rather than one number for the whole range. And a grade is a prediction under standard conditions, not a guarantee; real laundering, sunlight and sweat all vary.

Where colorfastness testing fits in sourcing

Colorfastness is checked at more than one point, and catching a failure early is far cheaper than catching it in bulk.

At the lab-dip stage, before bulk dyeing is approved, so a weak dye recipe is fixed on a swatch, not on thousands of meters.
On bulk fabric or the first production batch, to confirm the approved recipe held at scale.
At pre-shipment inspection, where colorfastness sits alongside the wider quality checks that gate the order.

For that to work, the requirement has to be written down. The tech pack should name the exact tests, the standard, and the minimum grade, so the mill and the third-party lab measure the same thing. A clause that just says must be colorfast is unenforceable.

When a fabric fails, the causes are usually predictable: unfixed or excess surface dye, the wrong dye class for the fiber, incomplete washing-off after dyeing, or a shade pushed darker than the chemistry can hold. Most failures are a dyeing and finishing problem, which is why colorfastness is really a manufacturing conversation, not just a testing one.

Colorfastness is one thread in a much larger sourcing picture: fiber, dye, mill, standard and end use, all connected. Apshan structures that fashion knowledge, cited to source, so those decisions are informed rather than guessed. Request access or see the plans and pricing.

Questions

What does a colorfastness rating of 4 mean?

A grade of 4 on the 1 to 5 grey scale means good colorfastness, with only slight and usually acceptable change or staining. Grade 5 is no change at all and grade 1 is severe. Most apparel programs treat 4 as a solid pass for color change, with 3-4 often accepted for staining.

What is the difference between colorfastness to washing and crocking?

Washing (ISO 105-C06) measures color loss and bleeding during laundering in water and detergent. Crocking, or colorfastness to rubbing (ISO 105-X12), measures color transferring by dry or wet friction, with no water or wash involved. A fabric can pass one and fail the other.

Why do dark colors fail crocking tests?

Deep, saturated shades carry more dye, and some of it sits on the fiber surface rather than bonding inside it. Friction, especially when wet, lifts that surface dye off, so dark denim and richly dyed fabrics commonly score lower on wet crocking. Specs usually relax the wet-rub target for dark shades.

Is ISO or AATCC better for colorfastness?

Neither is better; they are two standard systems for the same properties. ISO 105 methods are used widely in Europe and Asia, AATCC methods in North America, and most tests have a close equivalent in both, for example ISO 105-C06 and AATCC 61 for washing. The right one is whichever your market and buyer specify.

What causes poor colorfastness?

Usually a dyeing or finishing issue: unfixed or excess surface dye, the wrong dye class for the fiber, incomplete washing-off after dyeing, or a shade pushed darker than the chemistry reliably holds. Because the root cause is in production, colorfastness problems are best fixed at the dyeing stage, not patched afterward.

When is colorfastness tested?

At the lab-dip stage before bulk dyeing is approved, again on bulk or first production to confirm the recipe held at scale, and at pre-shipment inspection. Testing early, on a swatch, is far cheaper than discovering a bleeding dye once thousands of finished garments already exist.