The "pull" and "push" terms came
only from the lab world and referred
only to adjustments of development.
They were more recently appropriated by photographers who wanted to use them for descriptions of the
combinations of exposure
and development adjustments - typically "push" adjustments used to compensate for low light levels.
Historically, you would request a "pull" development from a lab because you had exposed a traditional, thick emulsion film to a scene with a wide SLR (Subject Luminance Range) and you sought to contract the resulting density range on the film, and thus the overall "contrast" of the negative. In Zone System terms, you requested "contraction" (N-1, N-2, etc.) development.
With
some films and some nominal characteristic curves, you needed to increase shadow exposure a bit to make that work.
On the other side of the coin:
Historically, you would request a "push" development from a lab because you had exposed a traditional, thick emulsion film to a scene with a narrow SLR (Subject Luminance Range) and you sought to expand the resulting density range on the film, and thus the overall "contrast" of the negative. In Zone System terms, you requested "expansion" (N +1, N +2, etc.) development.
With
some films and some nominal characteristic curves, you needed to decrease shadow exposure a bit to make that work.
Both expansion and contraction tended to affect how grainy the results were, so the size of the negative mattered.
Some people still approach it that way - use the adjustments to control the density range , and thus the overall "contrast" of the negative, and in response make any exposure adjustments to match. With most modern, thinner emulsion films, and with the smaller formats that most use now, the opportunities for using expansion and contraction tools are more limited than they once were.
In modern times though, most seem to reverse the approach - make the exposure choice first, and then see if changing the development can help with any problems. And then they frustrate the old lab operator in me by changing the terms!
If I understand it correctly - and my earlier question was intended to confirm that understanding - with this thread
@Garb is essentially trying to use a contraction approach with Harman Phoenix in order to tame some of its contrast peculiarities. In which case it would be useful to learn what, if any, exposure choices he/she has made as well to take into account the resulting changes - if any - in the light sensitivity of the "pull" developed film..
But if my understanding is incorrect, and
@Garb instead hopes to use a "pull" development to compensate for over-exposure instead, then the discussion is probably different.
