Human eyes cannot perceive infrared ink, as infrared light falls outside the visible spectrum. While digital cameras and camcorders equipped with CCD sensors can detect infrared light, many models include an IR filter to block this range. The discussion highlights that infrared inks can fluoresce under specific conditions, similar to UV inks, making them visible when illuminated with infrared light. For practical applications, devices like CCD chips are necessary to capture infrared images and convert them into visible light.
PREREQUISITESOptics enthusiasts, photographers using infrared technology, and researchers in materials science focusing on inks and fluorescence.
I've heard of "invisible" inks that fluoresce when illuminated with infrared light. (Similar to UV invisible ink, but on the other side of the visible range.) I assume the flouresence is visible--otherwise what's the point?derekbeau said:
Do a search on invisible inks.