Several years ago while taking a bowhunter safety class with a buddy to help encourage him in the sport I met a local man who was teaching the course. He brought in a lens he had purchased that filtered out the wavelengths of light deer can't see. According to a study done on whitetails that had been sedated they discovered that deer do not have color vision cones that perceive red. The do have cones that perceive some green and blue. It was amazing to see different shirts or pants light up on other people taking the course.
I contacted him and bought one of the lenses. The other day I started playing with it while out stump shooting. I think it will be fun to put my favorite clothes through the test to see what they look like in ground blinds and tree stands. Here are some sample picts. It is going to have to cool down a lot before I can start putting on my wools and other clothes.
Here are a couple of picts in the yard to show how reds drop out
Here are a couple in a ground blind.
Of course this lens can't make the uv show up as well as it does for deer since our eyes filter it out and deer's eyes do not.