Application of optical brightening agent on cotton:
Optical brightening g agents are easily soluble in water. These can be applied to fabrics just like the dyeing process. That is why they are called colorless dyeing. A special type of finishing process that uses brightening agents to whiten textiles and fabrics is called whitening. The use of a fluorescent brightening agent removes the yellow color and dullness of the fiber and makes the fabric whiter and brighter. https://bdfabric.com/stenter-machine-process-in-textile/
Method of brightening cotton cloth by Flowlight BW:
Recipe:
Flowlight BW → 0.5% (percentage of fabric weight)
Sodium chloride → 5% (percentage of fabric weight)
PH → 6 to 7
Temperature → 50°C
Time → 35 to 45 minutes
Brightening process:
The required amount of water is first taken in a container or padding mangle. The required amount of Flowlight BW is stirred well in the container. After raising the temperature of the solution to 50°C, a cloth is inserted into it. Then after 5 minutes 5% sodium chloride is added and treatment is done for 15 minutes. After 15 minutes, another 5% sodium chloride is added and treatment is done at 50°C for another 25 to 30 minutes. Then the cloth is thoroughly washed and dried. This increases the whiteness of the fabric and also increases the brightness.

Optical brightening agent-Method of brightening cotton cloth by Tinapol 2B:
Recipe:
Tinapol 2B → 0.5-0.8% (percentage of fabric weight)
Hydrolytic agent → 5 grains/liter
PH → neutral
Temperature → 40°C to 60°C
Time → 45 minutes
Brightening process:
Application of optical brightening agent on cotton. Bleached cotton cloth is treated with the mentioned ingredients for 15 minutes. The temperature is then gradually increased to 60°C and the cloth is treated for another 30 minutes. Then the clothes are washed and dried. This increases the whiteness of the fabric and also increases the brightness.