Light reactive chemical/ink

Discussion in 'Chemistry' started by Brightidea, Jul 5, 2008.

  1. Brightidea Registered Member

    I'm currently in the process of designing a product. It needs to work like invisible ink, but instead of reacting to UV light, I need it to show up when exposed to a normal bright light source. For instance if this clear ink was used on a piece of paper, then photocopied, it would show up on the print. Although the ink on the original piece of paper would remain invisible. I'm not sure if any chemicals used during the process of film developing would be useful? The chemical must be safe to use and be non permanent if used on glass. Any comments or suggestions would be greatly appreciated.

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  3. CelticMadScientist Registered Member

    Chemical-wise, don't know. I mean, if it's visible in visible 400-700nm or so light, it'll be visible regardless of intensity. The phospors in invisible ink just down-convert the higher energy UV light (higher frequency means more energy per photon E=hv) through a nonradiative means and then just emits visible light (like in floursecent bulbs, or anything that reacts with UV black lights, like bleach that makes clothes "brighter than white" in the sun.

    There are already measures in place for what you describe in the example. Grids and patterns on things like checks have patterns that look innocent on the original, but a poor photocopy will reveal big letters saying "not original." So maybe a optics solution to your chemical problem.

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