ann said:
More development =less contrast is not correct. More development = more contrast, that is why one pushes, to add contrast which also increases contrast. Basically pushing means underexposing, which means one has to over developed.
Ann, imagine what a negative would look like if you over-processed it by a stop or two. Is there more information in all areas of the neg or less? Hopefully you're thinking more!
You could keep processing until you end up with a solid black neg and on the way there your contrast decreases. More processing=less contrast (whether pushing the film or not.)
The higher contrast in a push process comes from underexposing the film. As the film was exposed without enough light to activate the silver properly the shadows in your negs have less detail. The highlights in your neg are also underexposed but the push process adjusts for that. As a push process can't invent detail where it never was though, you will end up with less detailed shadows (strong blacks) and fewer tones between those and the highlights. Consequently the negs and prints will have less tonal range.
Pushing neg film creates more contrast. Pulling neg film reduces contrast.
Shorter processing time=higher contrast
Longer processing time=less contrast
If you want to push film but retain as much tonality as possible use a dilute processor with a longer processing time. Similarly, if you want to put contrast into pulled film go for a stronger ratio and/or shortened processing time.
The same rules apply to correctly exposed film neg of course!
