Causes of color difference in denim

1. The color and light problem of the dye itself

At present, there are quite a lot of dye manufacturers, both domestic and foreign. The quality of denim production is also unstable. The quality of different manufacturers is different. The same dyeing factory produces different batches, and the shades are often different. In order to ensure the stability of the dyeing shade, before using the dye, the dyeing factory must conduct an assay on each batch of newly purchased dye, and compare it with the previous one to ensure that the shade is not far behind and the quality is stable.

2. Problems with the formulation of additives

The amount of dye auxiliaries has a great influence on the shade. Such as indigo, generally use caustic soda, hydrosulfite as reducing agent. The amount of caustic soda and insurance powder has a great influence on the color of the dyed indigo. When the amount of caustic soda is too large, the color will be reddish, and when the amount of caustic soda is small, the color will be cyan. The same goes for sulfur dyes and vat dyes.

When the amount of alkali is too large, the color light will be biased towards red light. Therefore, the dosage of additives must be strictly controlled when formulating. But the auxiliaries should not be too small, because once the auxiliaries are less, the color fastness of the dyed will be poor. Shade is "sub". In addition, like dyes, the quality of auxiliaries is also unstable, and testing should be carried out when each batch is purchased to check the quality, so as to ensure the stability of color and light.

3. Some auxiliaries will also have the effect of changing the shade

For example, some fixatives will have a cyan effect after being added. Therefore, when selecting additives, you must understand their functions and effects.

4. The impact of post-adjustment

In fact, this reason cannot be said to be that dyeing affects shade, because this is the effect of color after weaving. Generally, after weaving the cloth, if it is made of mercerized cloth, the color will turn red after mercerization. The alkali concentration and washing water during mercerizing have a great influence on the color and shade. The alkali concentration is large, and the color is reddish.

In summary, there are actually many reasons that affect the color and shade, so it should be summarized slowly in production, and attention should be paid to adjusting the shade according to the customer's board during operation. Make sure that the shade is as close to the customer's board as possible. In addition, there is another problem, that is, it is often difficult for many boot masters to distinguish between light and cyan. Generally, the color is lighter and does not look so red, but it is more cyan, and the color is darker, and it looks reddish. Especially indigo, obviously. Therefore, when judging, we must distinguish clearly the difference between light and blue.