How to prevent yellowing of laminated cotton fabrics Fluorescent brighteners are divided into two types, high and low in high-temperature performance, and low-temperature types can only bear <130-140 ℃, and high-temperature types can bear more than 200 degrees℃. When we choose fluorescent brightener, we must consider setting temperature on 180-185 degrees during the setting process. This temperature is definitely not adaptable to low-temperature fluorescent brighteners and is called yellowing.