Definition of reciprocity failure in English:

reciprocity failure

noun

Photography
  • Failure of an emulsion to follow the principle that the degree of darkening is constant for a given product of light intensity and exposure time, typically at very low or very high light intensities.

    ‘The next fact is that you also do not need to know anything about shutter speeds, zoom lenses, reciprocity failure or the like.’
    • ‘Now if you have read about time exposures you will have come across the phrase ‘reciprocity failure’ with long time exposures.’
    • ‘Those of you who have read books and magazines will have read about ‘reciprocity failure’ with long time exposures.’
    • ‘There's something called reciprocity failure which basically means that for exposure times above 1 second, the film takes longer to do what it should be doing and as a result, interesting qualities of light and shade develop.’
    • ‘I've always thought this was a deliberate affectation, the result - in the case of photography - of six years of art school spent learning about reciprocity failure, platinum printing and other arcane chemistries.’

Pronunciation

reciprocity failure

/ˌresəˈpräsədē ˈfālyər/ /ˌrɛsəˈprɑsədi ˈfeɪljər/