5 meters away from the observed object, place the electric torch between mouth and nose, then observe the light source.

Refractive Index:The refractive coefficient of glass bead to light. They are divided into series of 1.5Nd, 1.9Nd,2.2Nd.&...

Lightlead photoluminescent materials (commonly called “glow-in-the-dark”) has the ability to absorb light (sunlight, flu...

Many manufacturers refer to the extinction time of their products, which is defined as the time required for the aftergl...

Lightlead photoluminescent materials are non-toxic, non-radioactive and contain no phosphorus or lead, or any other haza...