Positive

positive: see photographic processing.

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positive [′päz·əd·iv]

(electricity)

Having fewer electrons than normal, and hence having ability to attract electrons.

(graphic arts)

Having the same rendition of light and shade as in the original scene.

(mathematics)

Having value greater than zero.

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Positive 

a photographic image in which the relative distribution of brightness, in black-and-white photography, or colors, in color photography, corresponds to the distribution in the object photographed. Thus, a positive is opposed to a negative, in which there is an inverse distribution of brightness or a registration of the image in complementary colors. Two types of positives are distinguished—those produced on photographic materials with an opaque support, such as paper or ceramic material, and those produced on photographic materials with a transparent support, such as glass or film; the second type comprises diapositives and motion-picture film positives intended to be viewed against a light source or to be projected onto a screen.

Positives are obtained by contact or projection printing onto positive photographic materials—the positive process. With this process, a large number of positives can be made from a single negative; with projection printing, positives can be made any size. Positives produced as a single copy, such as amateur motion-picture films and slides, are made on reversal materials by reversal process. In color cinematography, in addition to the negative-positive and reversal processes, the imbibition process is used, which produces positives from three color-separation black-and-white negatives.