Design Nomenclature / Light & Optics
Bloom
Also called glow, veiling glow
This entry has not been translated yet and is shown in English.
A post-process that bleeds luminance outward from the brightest parts of an image, standing in for scattering in the lens, the sensor's cover glass, or the eye's own media. It is applied to the finished image rather than simulated in the light transport itself.
In practice
Also the honest reason a display peaking at 300 nits can suggest a sun: you cannot make the pixel brighter, so you make it bigger.
Not to be confused with
- GlareVisual impairment or discomfort caused by a luminance in the field of view far above what the eye is adapted to. Disability glare measurably reduces what can be resolved; discomfort glare merely hurts. Both depend on the ratio to the adaptation level, not on absolute brightness.
- Lens flareArtifacts from light reflecting between the elements of a lens instead of passing through — ghosts of the aperture marching across the frame opposite a bright source, plus streaks thrown by the iris blades and any anamorphic geometry. Coatings suppress it; a strong enough source overwhelms them.
- Veiling glareStray light scattered inside a lens or an eye that lands more or less uniformly across the image, adding a luminance floor everywhere. It does not blur the picture; it lifts the blacks, which crushes shadow contrast while leaving the highlights essentially untouched.