Push processing.
Push processing is a technique that compensates for underexposed film by over-developing it at the processing stage.
The underexposure is usually deliberate - setting your camera to ISO 800 when there’s a roll of ISO 400 film installed, for example. But push processing can also be used as a last-ditch attempt to compensate for accidentally setting the ISO number wrong.
When used deliberately it’s useful for squeezing a bit more speed out of a slower film in low light. Generally pushing film by one stop (ie: doubling the ISO number setting) yields acceptable results, but going beyond that can be dodgy unless you have access to a very competent lab.
Push processing increases the contrast and graininess of the film and you usually lose a lot of shadow detail. Not all labs are able to push process film - minilabs often can’t - and those that can usually charge an extra fee for the service. Push processing is most commonly used with black and white and slide film, as colour print film has such wide exposure latitudes anyway.
cf. contrast, grain, processing, pull processing.
Entry last updated 2002-04-29. Term 979 of 1487.
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