Color fastness to washing measures how well a dyed or printed fabric keeps its color, and how much color it transfers to other fabrics, when it is washed. It is one of the most common tests in any garment test program.
What the test measures#
Two things are assessed:
- Change in color of the test specimen: has the fabric faded or changed shade?
- Staining of adjacent undyed fabrics: has color bled onto other fibers?
Common test methods#
| Method | Summary |
|---|---|
| ISO 105-C06 | Domestic and commercial laundering. A range of test conditions (letters and numbers such as A1S, B2S, C2S) with different temperatures, detergents and steel balls for mechanical action. |
| AATCC 61 | Accelerated laundering. One test cycle simulates several home launderings. Several test conditions (such as 1A, 2A, 3A) with different temperatures. |
| ISO 105-C08, C09, C10 | Other washing procedures used in some buyer programs. |
The buyer's test manual specifies the exact method and condition. Different conditions give different results, so compare results only when the method and condition are the same.
How the test works (principle)#
- A specimen of the fabric is sewn or placed together with a multifiber adjacent fabric: a strip woven with bands of different fibers (for example acetate, cotton, nylon, polyester, acrylic and wool).
- The composite is washed in a sealed container with detergent solution and steel balls (where specified), at a set temperature and time, in a laboratory washing machine.
- It is rinsed and dried.
- The change in color of the specimen and the staining on each fiber band are graded.
Grading with grey scales#
Grades run from 5 (no change or no staining) to 1 (severe change or staining), with half grades between (4-5, 3-4 and so on).
- Grey scale for color change (ISO 105-A02) compares the original and tested specimen.
- Grey scale for staining (ISO 105-A03) compares the stained and unstained adjacent fabric.
Grading is done in a standard viewing cabinet under specified light, or with an instrument using the matching ISO method.
Reading a report#
A typical report line looks like:
| Assessment | Grade |
|---|---|
| Color change | 4 |
| Staining: acetate | 4-5 |
| Staining: cotton | 3-4 |
| Staining: nylon | 3 |
| Staining: polyester | 4-5 |
| Staining: acrylic | 4-5 |
| Staining: wool | 4 |
Check the lowest staining grade. Nylon and cotton bands often stain most with reactive and direct dyes. Buyers usually set a minimum grade for change and for staining; always check the buyer's requirement for the product.
Why fabrics fail#
- Unfixed dye on the fiber surface after dyeing: poor washing-off (soaping) after reactive dyeing.
- Wrong dye class for the fiber or end use.
- Deep shades with high dye loading.
- Poor fixation conditions (temperature, alkali, time).
- Pigment prints with poor binder curing.
- Finishes (some softeners) that affect fastness.
Improving results#
- Better washing-off and soaping after dyeing, until the wash water runs clear.
- Correct fixation parameters.
- Dye selection with suitable fastness for the depth of shade.
- Fixing agents where appropriate, checking that they do not affect other properties such as light fastness or hand feel.
Linked problems in garments#
Poor wash fastness shows up as color bleeding onto white parts, labels and other garments in the wash. See color bleeding.
See also color fastness overview, color fastness to rubbing and color fastness to perspiration.
Related guides#
- ISO, ASTM and AATCC test methods: wash fastness methods by standard.
- Sustainable bio-scouring process: pretreatment that helps level dyeing.
- Fabric testing standards and methods: color fastness within the full test program.