Definition of halation in English:



  • The spreading of light beyond its proper boundaries to form a fog around the edges of a bright image in a photograph or on a television screen.

    • ‘The function of pyrazolone derivative in silver halide photographic paper is as a filter to prevent halation and irradiation.’
    • ‘With a regularity attributable to Therrien's use of templates, the forms share a richness and density and, often, a halation at each figure's thin edge.’
    • ‘If these are indeed the causes of halation, then I see no reason why halation should not also take place in a paper emulsion.’
    • ‘This gives normal contrast range with highlight halation.’
    • ‘The Sabatier edge effects, which appear as white lines between areas of distinctly different densities, were proven (by Stevens and Norrish in 1937) to be the result of diffusion halation.’


Mid 19th century: formed irregularly from halo + -ation.