Ultraviolet induced visible fluorescence photography
Sounds complicated, but it’s just shining UV light on an object in a dark room and taking a normal photo with long exposure. If you want to be pure about only picturing visible light, you might need a UV filter, since many cameras can already see a bit of UV despite inbuilt filters.
But physicists actually do that? They often write it like this: ∫ dx f(x) or this: ∫∫∫ dxdydz f(x,y,z)