Written by Gene Lafferty
A re children able to sense spirits more so than adults? The visible portion of the electromagnetic spectrum is generally from 380/400nm to about 760nm. UV or IR differs only in that there are some specialized cells in the retinas of our eyes that contain a pigment that gets excited when it encounters these wavelengths. Cats, for example, have a pigment that gets excited at shorter wavelengths, so they see a little bit into the UV-A range. Could this be a possible reason why cats sometimes act strangely in a reported haunted house? (Personally, I think cats are just odd in general, but that is for another article) The ‘visible range’ for a cat is different from the ‘visible range’ for a human. Here is the important part; very young children can see 380nm (which puts them into the UV range), where elderly people cannot see 400nm; so the ‘visible range’ changes even for humans.
At this point, you might be asking yourself “Why can I see some things in my digital camera that I cannot see with my eye.” You would be asking yourself a good question; here is the answer. That is because most digital cameras are somewhat sensitive in the IR range. The manufacturers of the camera actually build it with a device called an IR cut filter. An IR cut-off filter blocks the transmission of the infrared while passing the visible so the image more closely matches what you see with your eyes. Your typical infrared enabled digital camera, like a Sony with NiteShot, can see between 400nm and 1100nm.
Before I wrap this article up, I would be remiss if I did not throw a “shout out” to a pioneer in UV/IR technology. Trevor James Constable an author, aviation historian and investigator of unusual phenomena. His greatest contribution was his book, The Cosmic Pulse of Life published in 1975. All the way back in the 1950’s, he had modified an old, super 8 camera set to expose two frames per second, with an 18A ultra-violet filter attached. He shot the camera out the airliner window at thirty-five thousand feet. According to Constable, he was able to record UFO’s in full color, right through the UV filter.