ultraviolet light photography (black light)
see also:
infrared photography
http://photographyoftheinvisibleworld.blogspot.com.au/2011/01/simple-tutorial-for-reflected-uv.html
http://www.naturfotograf.com/UV_IR_rev01UV.html
beginner's guide to UV photography
UV wool, liquid, bubbles, etc
DIY UV Ring light modification with cellophane
https://www.dpreview.com/articles/3980259504/the-magic-of-ultraviolet-nature-and-macro-photography