Why is the sunscreen black when shooting with an ultraviolet camera?

The sunscreen in sunscreen absorbs ultraviolet rays first, and then converts them into lower energy to release them, thus avoiding the damage of ultraviolet rays. From the ultraviolet camera, the reflected ultraviolet dose becomes less, and the effect is black.

By reflecting ultraviolet rays, the physical sunscreen turns the original diffuse reflection of the skin into a mirror-like reflection, and the angle of reflection usually does not face the ultraviolet camera, so that less ultraviolet rays enter the camera and the effect will be black.