Wednesday, May 18, 2011

About push and pull processing

Push processing refers to intentionally over-developing a roll of film to allow the formation of additional density in the emulsion of the film. It can be accomplished by either increasing the time or the temperature during the formative development step. Pull processing refers to intentionally under-developing a given roll of film, i.e. giving it less time (or a lower temperature) than is recommended. Push and pull processing has become very popular with the new generation of film users, who enjoy experimentation and want unusual, even unpredictable results.

Original image, left; with 'push' processing, right.
All kinds of film (black and white, C-41, and slide/E-6) can be pushed/pulled, though the results on color film are typically less predictable (because of color shift in the layers) than those on black and white.  Film manufacturers, in general, did not recommend push/pull for color film because it results in a lack of natural color variance.  (For instance, a natural flesh tone could be very difficult to achieve in pushed color negative film.) But that has not stopped forward-thinking labs from doing it to accommodate their customers who wanted to break the rules or to salvage what might have been otherwise worse, due to under/over-exposure.

Original image, left; with pull processing, right.
The most common purpose for push/pull processing involves compensating for mistakes in the way that a given roll of film was shot.  So, for instance, in a case where you had your camera set for ISO 400 but you were shooting ISO 200 film, you might request ‘push’ to remedy mistake. In theory, if it were a very sunny day but you had only ISO 100 film, you might request pull processing. (The standard advice is that you should never try to correct more than one stop’s difference with pull processing.)

Hobby and art photographers often make use of push/pull processing to intentionally create unusual variations in color and saturation. Push processing is associated with higher contrast than you would get by processing film at its rated speed; conversely, pull processing tends to decrease contrast. In black and white, push processing tends to be particularly evident in the graininess of the image; where this texture is sought after, push processing may be called for.

Many photographers combine pull processing with cross-processing. Since cross-processing tends to increase contrast, this can be compensated for by pulling the film. The reason you would do this is to take advantage of the distinctive color casts of cross-processed film without all of the contrast of cross-processing.

It is important to note that different brands and speeds of film show entirely different results to the same temperature/time alterations.  For instance, a roll of Kodak Ektachrome 100 and a roll of Fuji Velvia 100 show wildly different color and saturation when cross-processed to the same formula. will be happy to push/pull your film; the option costs $2.00 per stop. We can go up to three stops push, and two stops pull. (We do not recommend either extreme, but we do offer it!)  Please clearly mark ‘push’ or ‘pull’ on the order form.

1 comment:

  1. Congratulations guys, quality information you have given!!!..Its really useful blog. Thanks for sharing this useful information.

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