Blooming

[1] A formation of an undesired thin surface film or a milky white haze or mist on paintwork. It is caused when paint is applied during humid, cold conditions as moisture is trapped in the wet film.
[2] Treatment of the glass-air surfaces of a lens with a deposit of magnesium fluroide or other substance, which reduces internal reflection and increase light transmission.
[3] Spread of spot on cathode-ray tube phosphor due to excessive beam current.
[4] Coating of dielectric surfaces to reduce reflection of electromagnetic waves.