Colour fastness testing for clothing: tests, grades and pass levels

Colour fastness (colorfastness in US spelling and in AATCC method titles) is how well a garment’s colour survives washing, rubbing, light, sweat and water without fading or staining other fabrics. Labs test it with the ISO 105 series (or AATCC methods in the US) and grade the result on a grey scale from 1 (poor) to 5 (no change), except light fastness, which uses a 1 to 8 blue wool scale. The tests are standard; the pass levels are not. Buyers set them in their own quality standard, and OEKO-TEX STANDARD 100 publishes a public minimum for staining that many use as a floor.

What does colour fastness measure?

ISO 105-A01, the general principles part of the series, defines colour fastness as the resistance of a textile’s colour to the agents it meets during manufacture and use. Each test produces two kinds of result:

• Change in colour: how much the tested fabric itself faded or shifted.
• Staining: how much colour moved onto an undyed adjacent fabric or rubbing cloth.

Other visible changes, such as shrinkage or a change in surface gloss, are reported separately and are not part of the fastness grade. A report that says “colour fastness: pass” without the two grades and the method number is not much use to a buyer. Our guide to garment lab testing in Bangladesh lists the accredited labs there and what else a usable report must show.

How the grey scale works: grades 1 to 5

Two grey scales do the grading. ISO 105-A02 assesses change in colour, and ISO 105-A03 assesses staining. Each is a set of paired grey or white chips. The technician compares the difference between the tested and untested fabric with the difference between the chips, under standard light, and picks the closest pair.

James Heal, which makes grey scales for testing labs, describes the ISO 105-A03 staining scale as nine pairs of chips running from grade 1 to grade 5, with four half steps. So the possible grades are 1, 1-2, 2, 2-3, 3, 3-4, 4, 4-5 and 5. Grade 5 means no visible change or staining. Grade 1 means severe change. Instrumental assessment with a spectrophotometer is also recognised in the series, which removes some of the judgement between two labs.

Light fastness uses a different scale entirely, graded against blue wool references, so a “4” for light is not the same as a “4” for washing.

The main colour fastness tests for clothing

US buyers may write AATCC methods instead of ISO ones. The principle is the same, but the procedures differ, so a result under one family does not replace a test under the other. Name the exact method in the specification.

Colour fastness to washing: ISO 105-C06

ISO 105-C06 tests a specimen stitched to a multifibre adjacent fabric in a closed container with detergent solution and stainless steel balls about 6 mm across, which add mechanical action. According to the standard, one single (S) test closely approximates one domestic or commercial laundering. One multiple (M) test may approximate up to five launderings at temperatures not exceeding 70 °C, and is more severe because of the extra mechanical action.

The adjacent fabric matters. For tests at 40 °C and 50 °C the standard uses a multifibre strip that contains wool and acetate. For some 60 °C tests and all tests at 70 °C and 95 °C it uses a strip without them, because hot bleach can damage wool. The standard also allows two single-fibre adjacent fabrics instead, one of them the same fibre as the garment. With a multifibre strip, the staining grade is reported for each fibre, so one report can show a very different grade on two stripes of the same strip. Read the lowest grade, not the average: that is the fibre most at risk in your customer’s mixed laundry.

Ask the lab which adjacent fabric it used. Two reports for the same fabric, one on a multifibre strip and one on single-fibre fabrics, are not directly comparable, and suppliers sometimes send whichever looks better.

Choose the test code to match the care label. A garment labelled for 30 °C should not be judged on a 60 °C test, and a garment labelled for 60 °C must not pass only because it was tested at 40 °C.

Colour fastness to rubbing: ISO 105-X12

ISO 105-X12 rubs a white cotton cloth over the fabric with a crockmeter, once dry and once wet. Gester, an instrument maker, summarises the key settings as a downward force of 9 N, a 104 mm stroke and a 16 mm rubbing finger for ordinary fabrics. The staining on each rubbing cloth is graded on the ISO 105-A03 grey scale.

Deep shades are where rubbing complaints come from: black, navy and red jeans or sweatshirts that mark a white sofa or a light bag strap. That is why both the dry and the wet result belong in the specification. OEKO-TEX STANDARD 100 accepts a lower dry rubbing grade of 3 for pigment, vat and sulphur colourants instead of its usual 4, which tells you those colourant types are known to struggle here. If your range includes pigment-dyed or sulphur-dyed garments, agree the rubbing grade before bulk production, not after.

Colour fastness to light: ISO 105-B02

ISO 105-B02 exposes the fabric to a xenon arc lamp representing natural daylight (D65), alongside blue wool references. The standard allows two sets of references: 1 to 8, preferred in Europe, and L2 to L9, preferred in America, and it states that results from the two sets are not interchangeable. On the European set, reference 1 has very low light fastness and reference 8 very high, and each step is roughly twice as fast as the one before. So the gap between grade 3 and grade 5 is about four times the exposure, not a small difference.

The test chamber’s humidity also changes the result, which is why the standard controls it with a humidity-test fabric. When you compare light fastness from two suppliers, make sure both labs used the same reference set and exposure conditions.

Light fastness matters most for outerwear, swimwear, caps, curtains and anything displayed in a shop window. For underwear or socks it is often a lower priority than washing and perspiration.

Perspiration, water and saliva

ISO 105-E04 soaks the fabric in artificial perspiration, in acid and alkaline versions, then presses it against adjacent fabric under load. Activewear, shirts and anything worn close to the skin in heat need this test. ISO 105-E01 does the same with water, which catches dyes that bleed when a garment is left damp.

For babywear, OEKO-TEX STANDARD 100 adds a saliva and perspiration test with reference to DIN 53160. If you sell kidswear, plan for it from the first lab dip.

What pass levels do buyers require?

ISO and AATCC do not set pass marks. The nearest thing to a public benchmark is OEKO-TEX STANDARD 100, whose February 2025 limit values include colour fastness to staining:

Source: OEKO-TEX STANDARD 100 limit values, edition 02.2025. For pigment, vat or sulphur colourants, dry rubbing of 3 is accepted.

Two gaps are worth knowing. OEKO-TEX grades staining only, not colour change, and it does not set limits for washing fastness, wet rubbing or light. Those levels come from the brand’s own quality manual. If you do not have one yet, write the method, the test code, and a minimum grade for each of colour change and staining, and ask the lab to report grades, not just pass or fail. Our certifications page explains which certificates partner factories can show and how to check them.

Dark shades, reactive dyes and garment-dyed goods

Most failures come from unfixed dye left in the fabric. On cotton, reactive dyes bond to the fibre, but any dye that did not react must be washed off. Cotton Incorporated’s printing bulletin describes a quick in-plant check: take a washed sample before drying, lay it face down on white fabric and press with a hot iron for 10 seconds. The white should stay clean. It is not a substitute for a lab report, but it is a useful question to ask a dyehouse.

Garment dyeing adds risk because the dye goes into the finished garment, seams and threads included. The garment dyeing and washing method explains how we handle it. As a rule, test every colour separately, not just the darkest one, and retest when the dye lot changes.

Putting colour fastness into your specification

• List each test by its method number and test code, and the minimum grade for colour change and for staining.
• Match the washing test temperature to the care label.
• Require wet and dry rubbing results for dark and bright shades.
• Test at lab dip approval, on bulk fabric before cutting, and on finished garments if they are washed or dyed after sewing.
• Keep the reports with the purchase order so every repeat is tested to the same standard.
• Decide in advance what happens when a lot fails: re-treatment or re-dyeing by the mill, a retest at a named laboratory, and who pays for each. Agreeing this before production is far easier than arguing about it with goods waiting at the port.

Add these lines to the testing page of your tech pack. Ask for the test reports before shipment, and for shade and colour transfer to be checked at the final inspection that our quality control service runs. To agree test requirements for a new range, send us your specification.