Time: March，2023

Cases: Glow in the dark powder mix with transparent ink and screen print on the cups

Problem Arising: The white glow in the dark powder gradually glowed blue after standing few minutes in the dark room

Analysis & Solutions：

This customer is developing printing logo on the cup to glow white in the darkness. He mixed white glow in the dark powder with transparent ink by screen printing onto the cups.

After finishing the sample, he placed the cup in a dark room for 30 minutes and observed every 5 minutes. He found that the glow color gradually changed from white to blue (as below picture shown).

Here is the reason for this phenomenon:

White glow in the dark powder is mainly physical mixed by sky-blue , red and a little yellow-green glow in the dark powder with different ratios. The glowing time of red glow in the dark powder is much shorter than the yellow-green and sky-blue, and the proportion of yellow-green is much lower than that of sky blue. The sky blue retains the longest time and becomes the main glow color in the end.

Therefore, with the standing time longer, the glowing color of red and yellow-green gradually weakened, the sky blue became the main glow color. That’s why the color gradually changed from white luminous to bluer luminous finally.

Hope this can help to understand more about white glow in the dark powder.