Positive-negative film is
instant
In physics and the philosophy of science, instant refers to an infinitesimal interval in time, whose passage is instantaneous. In ordinary speech, an instant has been defined as "a point or very short space of time," a notion deriving from its etym ...
photographic
film
A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, sinc ...
that generates both a positive print and a
negative from a single exposure on a single medium.
Polaroid Type 55, Polaroid Type 665, and Polaroid Type 105 are notable films of this variety.
References
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Photographic film types