- A glow observed on a photosensitive surface as a result of light being reflected by the front and rear faces of said surface. This may be observed, for example, as a blur surrounding a bright spot on the screen of a CRT when light is reflected on the front and rear faces of the glass. Also called halo (2).
- On a photographic image, a ring of illumination which appears around the image of a bright object. Also called halo (3).
- noun a patch of blurring around a light source on a photographic image, caused by light being reflected from the back of the film
- noun a halo effect in the light parts of a photograph, caused by light reflecting back from the emulsion