Push and Pull processing -

<p>I need to teach push and pull processing and have never done it - eek!</p>

<p >I understand the basics of how you do it - but what subject matter could I suggest to tudents with on how to approach these techniques?</p>

<p >High contrast lighting? Perhaps with window light?</p>

<p >Low Light and needing faster exposures? At a sports game indoors?</p>

<p >If you have any advice on interesting subject matter to approach the technique, I would love to hear!</p>

<p >thanks</p>

<p>The old adage is: "Expose for the shadows, develop for the highlights."<br /> Proper exposure of the shadows is critical to any image (on negative film). <br /> Any subject detail that's not on the negative won't be on the print.</p>

<p>Push and pull processing are needed to compensate for varying subject brightness ranges.<br /> They only affect the highlights, the denser areas of the negative. Shadow areas develop fully.</p>

<p>An example of a low-contrast subject that might require push processing would be a lake scene in early morning fog, with a boat house and a small pier.</p>

<p>A high-contrast subject might be a baseball game in bright early afternoon sun, with the white uniforms and the numerous shadow areas in the bleachers. You definitely want to hold detail in the uniforms, so pull processing is appropriate.</p>

<p>These techniques are better-suited to sheet film, where you can treat each sheet individually.</p>

<p>- Leigh</p>

<p>For pushing I would shoot people outdoors on a grey foggy day to show that pushing can put some sparkle into that grey.</p>

<p>For pulling I would shoot people outdoors on a bright sunny day to show that pulling can put some detail in washed out skin areas.</p>

<p>With 35 mm film available at a few dollars a cartridge I cannot understand the argument that pulling and pushing is better suited to sheet film. (How much is a sheet these days?). Mostly one shoots a series of pictures that need similar treatment anyway. And if not, use a pair of scissors to cut the film in half - or even thirds.</p>

<p>Some good starting advice above; Leigh's quote is indeed very valuable to remember.</p>

<p>And like Christer said, it's not limited merely to sheet film. As long as you shoot an entire roll of 35 mm or 120 film under the same conditions, you can process it the same way. I do that all the time.</p>

<p>Remember, though, there is a difference between pushing film and expanding the negative density range, which is what Leigh is really talking about above.</p>

<p>In pushing, you deliberately underexpose the film. This means that if you have 400 speed film in your camera, but that ISO won't provide you the proper combination of shutter speed and aperture to give you the depth of field and/or avoidance of blur (from camera shake, subject movement, or both) you're seeking, then you simply lie to your camera and tell it you're shooting 800, 1600 or whatever speed film and shoot according to the meter reading. Because the camera's meter thinks you're shooting faster film, it won't give a reading allowing properly full exposure of the film. <br>

If you do this, you will lose shadow detail because you are, as I said, underexposing the film. You'll normally get decent highlights and, hopefully, midtones as you will increase the developing time so that they end up being somewhat near normal. The film will be contrastier than usual, which is one reason for a film like Delta 3200: it's designed to be pushed without taking on too much contrast--and, in particular, burnt-out highlights--to print properly. As you mentioned above, pushing is normally done in low-light situations which may also involve rapid movement, like indoor/night time sporting events, music gigs, or theatrical performances. (Please do not advocate that your students shoot an actual live performance of the latter--they may get tossed out unceremoniously!)</p>

<p>In negative expansion, you expose normally or nearly so to give good shadow detail. But you may develop the film for 15-30% longer than usual in order to produce more brilliant highlights and greater contrast in the film. This is really an application of Ansel Adams' Zone System, and is covered in great detail in his (and others') books. This is indeed a good technique to use on a grey, cloudy day where there is not a great brightness range in the scene between the darkest bits (which are lit by diffused light coming from the entire sky) and the brightest.</p>

<p>Pulling film might best be tried out by beginners in bright sunlight, especially harsh midday light. The shadows in the scene will be very dark compared to the highlights. By reducing the film speed (say, exposing 400 speed film as if it were 200 ISO) you will give good generous exposure to the shadows. If you then reduce the development time (and possibly the agitation during development) you will, according to the saying, bring down the highlights so that they will not be unprintably dense on the negative.</p>

<p>In my experience, pulling is rarely done. There are much better ways to control high contrast situations -- flash fill and reflectors if it's a situation where you have that opportunity. If not, there's dodging and burning or the right variable contrast filter in the darkroom. And most modern film has sufficient latitude in exposure that it's not necessary. Only time I've seen it done is if a roll has been grossly overexposed, say three or four stops, by accident. Push processing is a different story. It was very commonly used in news and sports photography during film days. Back when 400-speed Tri-X was in every sports photographer's camera bag, pushing Tri-X to 800 or 1600 was standard practice for night baseball and football. Did it myself. I even had a Kodak publication called Student Pictures for Student Publications aimed at high school kids shooting for the school newspaper (which I did at the time). It had a section specifically on pushing film at poorly lit high school stadiums. If I were you, and trying to keep things simple for students, I would focus on push processing and use a sports situation as the classic example. For pulling, I would maybe show them a situation with gross overexposure and how to salvage it, but I would not try to encourage it as a means of contrast control since that is an extremely rare situation in day-to-day photography.</p>

<p>Thanks so much for your advice everyone!</p>