The Basics You Should Know about Color Fastness

The Basics You Should Know about Color Fastness
Image source: zhidao.baidu.com

It is inevitably that the textile fabric presents the phenomenon of color fading when doing daily cleaning, in particular, dark color jeans pant or other dark-color clothes. You may wonder that the reason why color fade happens? When it comes to this, you should know about the concept of color fastness. It is linked with the influences from internal factors and external factors of color fastness as last article mentioned. While, when it becomes finished products, only external factors reveal to people.

As its name implies, color fastness refers to the firmness of color, also called dyeing fastness. It interprets the resistance towards the physical and chemical processes during the process of textile color dyeing and use. Therefore, color fastness grade is the one of important indexes to evaluate the intrinsic quality of textile. It is a science to set the color fastness grade. The basis for judgement is the discoloration of sample and the staining of the undyed lining fabric, but not suits for all, there is an exceptional judgement for the color fastness to light and dry cleaning. Now, let’s probe into regular projects of color fastness under the various conditions.

There are nine projects of color fastness. Scroll down to see what are they and how to rate the fastness.

1.Color fastness to sunlight

It refers to the dye color change of colored fabrics under the exposure of sunlight. The test mode is to expose the color sample under the sunlight or sunlight machine, and then make a color fading degree comparison between exposed sample and standard sample. The rating standard are divided into 8 levels. 8 grade means the best color fastness. Instead, 1 grade is the lowest color fastness.

National standard gray card
Image source: mbd.baidu.com(National standard gray card)

2.Color fastness to washing

Washing fastness comes in two different types—washing and soaping. It is the evaluation about the dye color change of colored fabrics after washing and soaping. The color change further divided into faded and stained color. The way to rate the targeted clothes is to make contrast with gray fading color sample. 5 grade is the best, 1 grade is the worst. For stained color, using gray stained color sample makes comparison with stained sample on white cloth. 1 grade means it is stained seriously, and the converse 5 grade is no-stained. It is worthy mentioned that the temperature of washing has four options as per the washing stipulation of dyed textile.

3.Color fastness to friction

It refers to the situation of color loss after rubbing the colored fabric. The friction can be dry friction or wet friction. The evaluation of color fastness to friction is came out from comparing white cloth with gray card rating. The rating results are generally divided into 5 levels. The greater of rating value, the higher level of friction color fastness.

gray card1
Image source: mbd.baidu.com(Gray card)

4.Color fastness to perspiration

It refers to the discoloration of colored fabric after immersion in sweat. The sample is stitched with lining fabric and soak it in sweat, clamp it on the tester and put it in the oven at a constant temperature to dry it. After processing, rating with gray card to get the test result. The greater of rating value, the higher level of color fastness to perspiration. In the national standards and European standards, perspiration fastness is divided into color fastness to acid perspiration and color fastness to alkali perspiration.

5.Color fastness to ironing

It refers to the discoloration or fading of colored fabric after ironing. The rating grade from 1 to 5. The greater of rating value, the higher level of fastness. The test way of ironing fastness varies from fabric to fabric. The result is judged by the staining of discoloration and fading that the iron works on textile.

6.Color fastness to sublimation

It refers to the degree of sublimation of colored fabric during storage. The evaluation rating takes the gray grading sample card as standard. It divided into 5 levels. The higher the level, the better fastness. It is rated by observe the phenomena of discoloration, fading and staining degree of white cloth after dry hot pressing treatment of fabric. It is generally applicable to disperse dyes dyeing polyester fabric.

7.Color fastness to chlorine bleaching

The main target of chlorine bleaching is for swimwear products. Because of the chlorine content in the sea water, the fabric is easy to fade. There is also chlorine in tap water, and some hospital and hotel supplies are disinfected with chlorine-containing detergents. So, the requirements for chlorine-resistant bleaching fastness are improved. And the converse is the same, color fastness of non-chlorinated bleaching is to assess the degree of color change after washing under non-chlorinated washing conditions.

8.Color fastness to saliva

The sample is glued together with the specified lining fabric, placed in artificial saliva, after treatment, the test solution is removed. Then put the sample in the test device clamp the sample with two plates and applied the specified pressure to make them dried respectively. Lastly checking the color change of sample and the lining fabric contrast with gray card.

9.Color fastness to peroxide

The reason for fading of color fabric during washing partly down to oxidation. Mostly washing powders are added with peroxides such as peracetic acid and some activators, which is the reason for its oxidation. So, the fastness to peroxide is also one of the contents of the fastness test projects.

peroxide resistance test card
Image source: mbd.baidu.com(peroxide resistance test card)

Hereby, we have acquired total nine color fastness projects. By these projects, we can know that color fastnesses are subjected to various external forces. Essentially, the external factors reflect the requirement to the internal factors because it is modifiable factors to improve fastness.

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