Many longarm machines offer a Black Light option when quilting which allows the quilter to see certain threads better. What makes some dyed threads "glow" under a black light?
Superior Threads Chemistry 101 - A black light (bulb, LED, or tube) gives off ultraviolet light which happens to be highly energetic. The human eye can't see this light of the spectrum. (This is perhaps why it became known as "black light".) Fluorescent substances absorb the ultraviolet light and then re-emit it almost instantaneously. Threads which are dyed with fluorescent pigments or threads which are bright white will absorb the black light and reflect it back in a wonderful glowing sheen.
Here is a selection of our threads viewed under standard fluorescent light
And the same thread selection viewed under a black light
Here is a list of our threads that glow under a black light:Bottom Line #621