a) The semi-products before dyeing do not meet the requirements. If the dyed semi-finished product has insufficient mercerization, the mercerization will be alkali-colored, which will change the shade. For example, after sulfide dyeing, the cloth surface will be red and not black.
b) Hard water is used for dyeing. Dyes that are sensitive to hard water can easily cause dyeing defects. For example, direct pink 12B, direct light fast blue RGL, etc. will become lighter in hard water, which does not match the color standard.
c) Improper management during dyeing affects the dyeing effect. For example, in the dyeing of insoluble azo dyes, the semi-finished fabric does not develop color immediately after the base is placed. If it is left for too long, the naphthol on the base fabric is decomposed under the influence of air, and the color becomes lighter.
d) The dyestuff is weighed and weighed incorrectly, the dosage is inaccurate, and it is not found in time during the dyeing process, and the dyed color does not match the standard sample.
e) The process conditions must be strictly controlled during the dyeing process. If the process conditions are not well controlled, such as temperature, humidity, concentration, pressure pH value, vehicle speed, and drying conditions are unstable, fluctuating high and low, it will affect the color of the product.