How to Control the Color Difference of Jeans Fabric?
In order to produce denim that meets the color requirements of customers, manufacturers need to strictly compare the color difference of products. This article mainly analyzes the reasons for the color difference of jeans fabrics and how to control the color quality using portable colorimeter.
I. Why will the denim fabric has color difference?
In the production process of denim fabrics, it is easy to have defects such as side-to-side color aberration, head-to-tail color aberration, stains and cylinder differences. If the color quality of the denim fabric is not enough, then the finished clothing produced will also be difficult to pass the quality inspection. The main reasons for the color difference of denim fabric are as follows:
1. Color difference in side
The surface of the padding roller is worn and the pressure of the padding roller is uneven; the veil is uneven during drying after washing and the difference is caused by the uneven degree of drying.
2. Head and tail color difference
One is that the yarn wrapped around a certain guide roller needs to be processed at a slow speed. The other is that the liquid level changes. And the circulation pipe of the dyeing liquid is blocked, so that the dyeing liquid cannot be replenished in time.
3. Color spots
There are many scattered spots and there is generally no special pattern. The reasons are as follows: mixed foreign fibers in the raw cotton blending process cause uneven dyeing and unavoidably appear white spots; uneven yarn twist causes uneven dyeing; when the warp tension is set too large, the yarn is slack. Self-twisting into “braid knots”, the “braid knots” were not opened during dyeing and could not be dyed evenly. When rewarping, the “braid knots” were pulled apart to form white spots due to tension.
4. Cylinder difference
There is a small amount of residual night after dyeing in the previous tank and various dyes exist in the residual night. Due to the different dye uptake rates, the dyes are added more times during the continuous tank dyeing process, resulting in larger errors and resulting in poor tanks.
In order to prevent and solve the problem of dyeing and color difference of denim fabrics, it is necessary to test the colors of dyes, semi-finished fabrics and finished denim before dyeing, semi-finished products and finished products to maintain the consistency of the color performance.
II. Colorimeter achieve the color quality of denim fabric
To control the color difference of jeans fabrics, manufacturers generally choose a portable colorimeter. The colorimeter is easy to operate and can accurately assess the color difference between the two colors.
Portable colorimeter measuring principle: when the light finds the object surface, the light that has not been absorbed by the object is reflected through the object surface and enters the three filter colors of red, green and blue. The monochromatic light from the color filter enters the photoelectric detection head, so as to directly calculate the tristimulus value XYZ of the object color. The accuracy of the results of measuring the chromaticity parameters of the portable colorimeter has a great relationship with the quality of the color filter. Linshang portable colorimeter display the Lab and Lch values after the color measurement. This color measurement tool also has QC testing function. If the ΔE*ab (0-50 can be set) exceed the value that you set, the portable colorimeter will indicate NG which means the color difference is too large.
In the production process of denim fabrics, in order to control the color quality of the fabrics, the operator can directly use the portable colorimeter to test the color of standard sample (or color cards, swatches) and the color of test sample to determine whether the color difference of the produced fabrics is qualified.