by Asia Quality Focus team
The color fastness test is one of the most popular, in the textile industry, during a first article inspection, production inspection or pre-shipment inspection. However, for the color fastness test on dyed yarn fabric, the process should be different. It is recommended it to be performed at an earlier stage. What is a color fastness test? How does the dying of yarn fabric work? When should the color fastness test on dyed yarn fabric be performed?
The quality inspector in charge should take a white cloth and rub it against the fabric with adequate strength. The test is done twice: the first time with a dry cloth, the second time with a wet cloth. If traces of color appear on the white cloth it means that color transfer occurred.
The dyed yarn fabric follows a different production process than other fabric: the yarn is dyed first, and then colors are set using a fixing agent. Afterwards the yarn is dried, sized, beam-warped, weaved, desized, etc. to finally get the finished yarn fabric.
The color fastness test on dyed yarn fabric is more complex, as it involves several different pieces of yarn which may have been dyed differently. Moreover, yarn fabric can be made of the same yarn color or mixed colors. Each yarn has been subjected to a different dying process.
Different strands of yarn are crossing one another which makes it even more difficult to understand which one is fading and to evaluate the actual color fastness grade. As a result, the color fastness test should be done at the very early stages. It should occur after the dying of the yarn instead of on the fabrics.
As a result, the color fastness during an inspection is almost meaningless. That’s why this test is often excluded from the inspection protocol. To know the color fastness grade of dyed yarn fabric, the test should be performed during the dying process instead of on the finished yarn-dyed fabric.
The color fastness test, during an inspection, is only valid for dyed fabric that underwent the dying process in the last stage of the fabric manufacturing, as opposed to the yarn fabric for which it is usually the first step.
And you: when do you perform the color fastness test on dyed yarn fabric?
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