Pushing film - underexposed results?

Discussion in 'Film and Processing' started by craig_luck, Oct 3, 2014.

  1. Hello all,
    I am new to the forum and a new user of a wonderful Rolleiflex 2.8E2. Also new to the medium format!
    So, I photograph the street in B&W. I often push my Tri-X 400 stock to 1600. I do this because I want to shoot at 1/250 shutter and a wide open aperture of f22 - for focus reasons.
    I set my meter to perform as so and dialed in all the correct measurements for the day. It was sunny with heavy clouds, but I metered regularly to make sure I was on top of it. Of course, I informed the lab to push to 1600 as well.
    My results, though, have come out underexposed. Some much more than others. I am shooting through a Rollei orange filter (for the B&W contrast) so could this be underexposing my images so dramatically?
    Any theories and answers would be greatly appreciated.
  2. A couple of thoughts: are you certain the lab actually push processed your film? Second, there may be some confusion about exposure readings and settings. f/22 is actually stopped all the way down, meaning less exposure, not "wide open" as your post stated. Wide open would be f/2.8, at the other end of the settings. To attempt solving the exposure mystery, your orange filter subtracts probably 1.5 or 2.0 stops and should be factored in to the calculations. A "Sunny Sixteen" rule of exposure is to set the reciprocal of your ISO, at f/16. At f/22 an ISO 1600 full sunlit setting would be 1/3,200th second. Factor in your orange filter, and it would be between 1/1,600 and 1/800th sec. If the light was "sunny with clouds", that would require another stop of increase, from "sunny sixteen" conditions, or around 1/500th sec. @ f/22. If you exposed at 1/250th sec., f/22 you should have actually seen one stop of overexposure (greater, not less developed silver density) in your negatives pushed to ISO 1,600. So something is amiss. I suspect the lab didn't give you the push processing, and that would explain the thin negatives returned to you.
  3. Howard, wouldn't Sunny Sixteen at his ISO be f16 at 1/1600, without compensation, rather than 1/3200? f22 would then be 1/800 second. Filter adding two stops would be 1/200. Sunny with clouds would be 1/100 second??
    Craig, with B&W film I bracket two stops either side of the "calculated" exposure. With color film, I would only bracket 1 stop, and with slides only 1/2 stop. By bracketing 2 stops either side with the latitude of B&W film, one of those exposures should give you a usable negative.
  4. Stephen's calculations are correct. So if you were shooting f/22 at 1/250 with an orange filter and clouds you were underexposed by a full stop even if the lab pushed your film properly. You have to take the filter into account in setting your exposure.

    Do you need the filter? I typically use a yellow or red filter to darken skies or bring out texture but usually don't use a filter with people. The yellow filter only costs one stop of exposure rather than the 1.5 or two for the orange. If you simply want to increase contrast you can do that when you make prints.
  5. Thanks, for baling me out, Stephen and Craig. You're right.
  6. James G. Dainis

    James G. Dainis Moderator

    You don't say what the exposures actually were so I will assume they were 1/250 @ f/22. But that doesn't really matter. Shooting 400 ISO film with the meter set at 1600 ISO means you underexpose by two stops. Period. If you didn't meter through the filter you underexposed by three stops.
    Push processing, giving extended development, does not raise all values. Shadows stay where they are and only higher lighter values can be raised. Some values would be:
    Zone 1 = black no detail
    Zone 3 = dark sweater with weave, shadow detail
    Zone 5 = gray card
    Zone 6 = face/flesh
    Zone 9 = white shirt with some detail
    Underexposing by three stops would get the sweater dropped to pure black,
    the gray card dropped to almost black zone 2,
    the face value dropped to zone 3, very dark gray
    and the white shirt dropped to zone 6.
    Giving a two stop push would raise the white shirt from zone 6 to zone 7-1/2 but the face values and gray card would stay just about where they are badly underexposed. One could raise the values in printing but the whites would go off the chart as blocked highlights, and the lower shadow areas would still have no detail, clear on the film. Giving less enlarger exposure to raise the face value up to zone 6 would mean all the shadows get less exposure and would appear gray not black.
    You do not push film when shooting 400 ISO at 1600 ISO. You are underexposing the film. The dark tone values are lost, not recorded on the film. Trying to get them back in processing will not work.
  7. Wow - thank you for the replies. Most appreciated to all.
    I believe my mistake is a combination of things. Not factoring in the orange filter at the time of shooting is the main one, however. I didn't realise it could stop it down so much (1 or 2 full stops).
    The second is that the prints are quite dark anyway, it would seem. I had the negs scanned too and from the CD they are actually exposed okay.
    Howard, my "wide open" description was a typo. ;)
    Craig, I'm experimenting at the moment, so I may well end up not requiring/liking the orange filter.
    Thanks again!
  8. Push processing inherently involves underexposing. Pushing is just giving underexposed film additional development in an attempt to salvage the image, or in some cases for the grainy, contrasty artistic effect. But pushing does not give much additional true speed. Some combinations of film and developers might boost the true speed 10-25%. Other developers might actually lose speed, compared with the ISO standard developer used by the manufacturer in establishing the film's rated ISO.
    Several years ago an Ilford representative said their tests showed HP5+ in Microphen or DDX had a true speed of 500, per the usual ISO standard for lowest measurable density over film base and fog. But I found that particular combination to be more grainy and contrasty than I liked. HP5+ suited my personal aesthetics better rated at around 200 and souped in ID-11. And no amount of additional development will turn an ISO 400 film into an ISO 1600 film. There's always some trade offs, usually in loss of shadow detail, increased grain and contrast.
    By the way, any time you underexpose film with the intention of push processing, be sure to develop the film promptly. The latent image is less stable with underexposed film and any faint shadow detail that might have been recorded will fade. In my home tests I saw significant loss of latent image after only a month when pushing ISO 400 films like Tri-X and T-Max 400 to 1600. It's the difference between contrasty with some tonal gradations, and soot and chalk with no gradations in between. So I always try to be ready to develop underexposed film the same day I finish the roll.
    If you don't develop your own film, or can't process it immediately after exposure, it's better to avoid underexposing film. Film exposed at the rated ISO or more generously (such as rating an ISO 400 film at 200-320) will help ensure a more stable latent image that will still be there months or even years later - although fogging becomes a problem after too many years.
    Regarding the Rollei and orange filter, that was one of my favorite combinations for b&w landscapes and architectural studies. But I used that combination with ISO 100 film at the rated speed, avoiding underexposure, and usually from a tripod. For handheld street photos with the TLR I avoided any filters.
    For one thing, the orange filter doesn't accomplish much unless a blue sky is a significant part of the scene. It darkens a blue sky and helps define clouds. But the orange filter won't have much effect on most tonal values in the scene. It just robs you of a couple of stops of light and forces you to make compromises that aren't necessarily compatible with handheld street photography. It may even have unwanted effects such as darkening a person's brilliant blue eyes in portraits, rather than rendering them lighter gray as most b&w film will do when used without filters.
    Remember: "contrast" filter don't really uniformly affect contrast throughout the scene. Yellow, orange, red, green and blue filters only selectively affect the monochrome rendering of certain colors. So unless there's a specific reason to use an orange filter, it's usually best to avoid it - especially for handheld street photography. You can often better control overall contrast with development, and printing or scanning and digital tweaking.
    Also, if you're shooting in daylit urban areas, you're often dealing with extreme contrasts between sky and subjects in deep shadows. If you expose for the sky, the subjects in building shadows will be barely discernible. If you expose for subjects in shadow the sky will be blown out. So don't expect much from a straight print or scan. A lot of darkroom/digital wizardry goes into wringing out the image you want.
    Most photojournalists, street and documentary photographers and/or master printers who work with b&w film in these conditions expect to do a lot of manipulations during printing: dodging/burning, selective application of yellow/magenta filters on variable contrast paper, even some bleaching/intensification for some really tricky prints. Those great looking dramatic, moody, contrasty street scenes don't just fall out of the camera. They're often the work of a master printer who understands what the photographer wants to accomplish.
    If you're not doing your own processing you might ask the lab which developer they're using. Some developers are better than others for pushing Tri-X and other films.
  9. Fantastic and detailed response Lex. Hugely appreciated and fine reading. Thanks
  10. With a speed enhancing developer and low contrast lighting an E.I. of 1600 might be acceptable for some users. If lighting is not low contrast, anything above E.I. 800 might not acceptable. Between the developer and fixer a water bath for several minutes might allow some additional shadow detail to show up, but as others have said, increasing development does more for the highlights than the shadows. Diafine works well for Tri-X, but the recommended E.I. of 1600 is too high for my tastes. I prefer around 1200 for Tri-X in Diafine.

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