reversal

Definition: (1) Process in which a normal negative-working reproduction is made to produce a positive-working image e.g. black & white negative film may be processed as normal until before fixing, when it is re-exposed and bleached to remove the negative image, which leaves behind a positive image. (2) Effect seen when a second exposure, either before or during development, reduces the effect of the first exposure e.g. Clayden, Sabattier effects. (3) Result of extreme over-exposure: instead of high density of image, there is a low density e.g. when sun is photographed, may show a dark centre. * Also known as solarization.

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