Catch light

The technique is effective in both still and motion picture photography; helping to draw attention towards the subject's eyes, which may otherwise get lost among other elements in the scene.

In a patent for an Image Editing Apparatus, a catch light makes it "possible to emphasize or add to an expression on a subject's face".

Its process reflects light from the surface of the cornea by a built-in flash unit, and is then exposed by an "image pickup element".

Typically, this trope is represented by computer magnification of an image to gain information about the surroundings of the person being photographed, essentially using the eye as a mirror.

Audiences usually perceive eyes without specular highlights to be lifeless or evil, and for this reason many cinematographers specifically eliminate catch lights on antagonistic characters.