Shane we do agree and yes lower in frequency - longer in wavelength.
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Shane we do agree and yes lower in frequency - longer in wavelength.
I believe what has happening is that the brightening agent added to the material begins to fluoresce under a light heavy in ultra violet. The same thing sometimes happens to ladies facial makeup and that gives a clownish look to the woman's face.
This seems to have been more of a problem with earlier electronic flashes that did not have UV filters incorporated in the flashtubes.
A way to prevent the florescence is to filter out the U.V. from the flash. Just using a UV filter on the lens will not help because when the colors begin to fluoresce, they are in the spectrum of visible light so a UV filter will do nothing...