Luminous powder commonly used particle size mesh and micron:

Powders smaller than 400 mesh cannot be physically screened.

100 mesh – 100 to 110 microns

200 mesh – 50 to 60 microns

250 mesh – 30 to 40 microns

400 mesh – 20 to 30 microns

Ultra-fine powder: average particle size 10 microns.