Main purpose of Pushing/ Pulling:
1) Compensate for unexpected lighting
2) Pushing to achieve grains
To Increase contrast:
2) Develop at higher temps/ Concentration (the shorter the development time the higher the contrast)
3) Printing with higher contrast filters/papers
4) Developing Prints with developer at higher concentrations (same theory as film process)
to and extent, pushing ya film might help to increase the contrast.
but ya lose some ya gain some.
it differs from film character.
altering the developing process might be a better means other then to use filters that'll reduce the exposure or losing highlights and shadows from pushing.
delta on rodinal can work magic is ya're not afraid of the grains.