What is washing fastness for a fabric?

Washing fastness is a term used to describe the ability of a fabric to resist fading or running of colors when it is washed. It is an important characteristic of textiles and is determined by testing the fabric under specific conditions to evaluate its colorfastness after washing.

The washing fastness of a fabric is affected by many factors, including the type of dye or pigment used to color the fabric, the quality of the dyeing process, and the type of washing method and detergent used. Generally, fabrics with good washing fastness will retain their original color and appearance even after repeated washing, while those with poor washing fastness may fade or bleed, resulting in a change in color or staining of other fabrics.

To determine the washing fastness of a fabric, standard tests such as ISO or AATCC are performed under controlled conditions using specific equipment and procedures. The results are typically expressed on a scale from 1 to 5 or 1 to 8, with higher values indicating better washing fastness.

How to test the washing fastness of fabric?

The washing fastness of a activewear & sportswear fabric can be tested through the following steps:
Cut a small piece of the athletic wear fabric to be tested, and mark it with a waterproof pen or marker.
Wash the fabric piece in a washing machine using a standard detergent and water temperature according to the fabric care label. Use a gentle cycle if the fabric is delicate.

After washing, hang the fabric piece to air dry.

Once the fabric is dry, compare it to an unwashed piece of the same fabric under the same lighting conditions to observe any changes in color or texture.

Repeat the washing process several times, following the same steps, to test the durability of the fabric.

Compare the results of each washing cycle to determine how well the fabric has held up over time.

It's worth noting that some fabrics may require specific washing conditions or detergents, so it's important to follow the fabric care label and any other specific instructions provided by the fabric manufacturer when testing for washing fastness. Additionally, some professional textile testing labs can also perform washing fastness tests using more sophisticated methods and equipment.

Washing fastness is very important to making apparel, so we would do it before making your garment sample or mass production.

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