Push Processing!

OK.

I learned Push and pull processing in college...but for the life of

me I have forgotten because I had a photography hiatus for 6 yrs.

Please someone explain the process and uses of this to me again. It

would be greatly appreciated.

I have been looking for a way to get more robust negs. Would this

be a way?

Jaselyn, It depends on what your definition of "robust" is. Pushing film is not my idea of robust, but if you like the grittier street look it produces, then it might be your idea of it.

Push processing is used for film that is underexposed, usually by tricking the light meter into thinking the film is faster than it is. For example, 400 film is shot at 1600. To compensate for the lack of light striking the film, you "push" the film by developing it longer than normal to bring out the underexposed parts of the image.

This usually increases grain (often objectionably), but also tends to increase contrast depending on the film / developer / speed combo that you're using. I see no reason to "push" film unless you like these characteristics, or simply don't have enough speed to hand-hold the camera or something.

When we push process what we get isn't so much more "robust" negatives as contrastier, grainier negatives. Sometimes, tho', this is precisely what we want for a particular flavor.

There are many discussions about push processing here because I and several other photographers who participate on the b&w forums are diehard (i.e. "reckless") push processors. Search the archives for detailed discussions and recommendations.

Basically, when we're talking about pushing we're talking about underexposing the film and compensating with extended or otherwised "enhanced" development.

Twentysomething years ago when I was a photojournalist I rarely needed to push Tri-X beyond 800. I used HC-110 more or less normally (Dilution B) and added 25% to the recommended time for exposure at 400. Simple, reliable.

For the past few years I've been using either Microphen or Diafine. Both are more effective speed enhancing developers. They're also very different so it's important to study up on these differences. Development time in Microphen can be adjusted to suit your needs; Diafine pretty much ignores differences in time and temperature variations.

When I plan to use Diafine I shoot Tri-X at 1250. Any more exposure and the negs tend to become gray with poor separation. Any less exposure (such as 1600, as the maker of Diafine suggests) and more shadow detail is sacrificed than I care to give up.

When I need more flexibility in exposure, such as exposing Tri-X (or, sometimes, TMY) at 1600-6400, I'll use Microphen. Like D-76, HC-110 and many other developers, Microphen's effect *does* respond to variations in time, temperature and agitation.

I can't offer specific recommendations because there are too many variables. Dig out some of the previous discussions as a starting point.

If you can't find Microphen (since Ilford's problems) try Acufine. Reportedly Xtol is a pretty good speed enhancing developer too.

I've been having luck using Kodak T-max developer diluted to a one-shot. So far I've been using one ounce of concentrate to 15 oz. water, which is 1/4 the usual concentration. I process the 35mm roll in a 16 oz. tank to make sure that there will be enough developing agent present to do the job. It is possible that 1/2 oz. to make 8 oz. of developer would suffice, but I haven't had time to waste a roll to find out. At any rate, I am able to shoot HP-5 or Tri-X at 1600 this way without seriously blocking the highlights. Developing time so far is 19 minutes at 72 degrees, with very minimal agitation. I would say that this is pushing, not only the film, but the envelope, though, as there is admittedly only marginal shadow detail. Certainly 1250 or 1000 will give a better picture, not "robust," but better than 1600. Pushing Tri-X or HP-5 to only 800 is much better when a higher speed is not needed. I don't know that I would call the result robust, but the negative is at least adequately exposed. At 1600, I am giving up most of my shadow detail.

Actually, I feel that there is a certain amount of make-believe in "pushing" film more than about 1 to 1 and 1/2 stops. You can set your meter to anything you like, but that doesn't mean you really made the film 2 stops faster. You are just giving up some detail in the darker parts of the picture. It is just a question of how much you will give up, with some film/developer combinations doing a little better than others. When we push, we are just working at the edge of the film's latitude, or beyond it. When I expose Tri-X at 1600, I am very careful to base my reading on the middle or mid-to-darker tones, excluding any streetlights or other bright areas from the reading. This kind of care during the photography is necessary, IMO, when "pushing" film--and just as important as anything we do in the darkroom.