6 Color Glow in the Dark SAMPLE Set Day Visible Fluorescent Strontium Aluminate Pigment powder

First off, the blue and purple were total duds when it came to any glowing action, both with the provided tiny flashlight and with a more powerful light 400nm light bar I have. Yes, I know the packaging says 365nm is the optimum wavelength, but that's less common and if it needs specialized lights then that's a drawback.Second, this doesn't mix well at all in epoxy resin. AFAICT part of the problem is that the grain size is uneven. What I get is a surprisingly opaque result from the smaller grains, plus larger grains that have floated to the top (typically the *bottom* of the finished product). I'd try heating it more, but the packaging is pretty clear that it doesn't handle heat well either. Maybe I shouldn't expect it to work in resin, that it's designed for use in other kinds of materials, but again that's a significant drawback.FWIW I've tried many kinds of phosphorescent, fluorescent, and other powders before. Some of them do sink or float or otherwise not mix perfectly, but this one has been the poorest performer so far.