Fun With UV Light - Stamps Authenticity

When I was little I collect stamps. Not much mostly local stamps. Here we see Hong Kong stamps having glowing kanji writings when shone with black light.
Then later inspected a series of old Italy stamps, and one of them is clearly a fake one. Old papers do not have fluorescent chemicals added to them so they do not glow under black light.

[@zachkauffman6399]

Can you do another video explaining a few extra things, such as if you can use blacklight to see watermarks on the back of older stamps, the discrepancy between older watermarks & newer methods of marking stamps, & what the legitimacy of these glowing stamps is compared to others. I was very happy to see the chinese character on that Hong Kong! Also wondering if a cheap blacklight/flashlight works as well as a chemical bath... thank you for sharing this with us!