A glow in the dark pigment, such as zinc sulfide, can be used to demonstrate how images can be made with light and a photoactive material.
In a completely darkened room, make a thin layer of the zinc sulfide pigment and then use a flash of light, such as a camera flash, to photoactivate it so that it phosphoresces. You can turn this into a nice demonstration by placing your hand over the layer of zinc sulfide. When you use your camera to photoactivate it, you will see the image of your hand left behind.
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