Tips on using Ilford SFX 200?

Discussion in 'B&W: Film, Paper, Chemistry' started by f/16, Jun 19, 2013.

  1. f/16

    f/16 Subscriber

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    I'm thinking of trying a roll soon. Does it have to be loaded in total darkness? Which filters give the strongest IR effect? Which ISO is best to shoot it? Do many local labs process it? Will some cameras fog it?
     
  2. Jon Shiu

    Jon Shiu Subscriber

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    Hi, you can info on ilfordphoto.com
    I like to use a R72 filter, in camera slr meter at ISO 12 with filter off, focus, compose and then put the filter on. Of course, easier to shoot with rangefinder camera. Processes same as conventional black and white film.

    Jon
     
  3. thefizz

    thefizz Member

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    You will need the R72 filter, any lighter filter will not produce much IR effects. Don't worry about loading and unloading the film, just keep you back to the sun when doing so. Your camera will not fog it. Any lab developing B&W film should do SFX also.
     
  4. Gerald C Koch

    Gerald C Koch Member

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    From the Ilford data sheet http://www.ilfordphoto.com/products/product.asp?n=12#

    "Hoya R72 and Kodak Wratten 89B. These
    filters give an even more dramatic effect than deep red
    filters. However, exposure times with these filters can be
    very long, so the use of a tripod is recommended.
    "

    If you look at the spectral response curve for this film you will see that the infra-red sensitivity peaks at 720 nm and falls off very steeply at longer wave lengths. This causes exposures to be very long with this filter. This filter also requires an exposure increase of 4 stops. It would be wise to bracket your exposures.

    If the exposure times become a problem then try a Wratten 29 filter which requires only a 1-2/3 stop increase in exposure and produces similar results.
     
    Last edited by a moderator: Jun 19, 2013
  5. kevs

    kevs Member

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    1: No, load normally.
    2: I've had good results with a Hoya 25A red.
    3: I had good results exposing at EI 50 (+ 2 stops).
    4: Yes, as long as they develop standard B&W film (not c-41).
    5: Not unless there's a light leak that will fog ordinary film.

    Cheers,
    kevs
     
  6. f/16

    f/16 Subscriber

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    Hey, thanks for all the help guys. I have a 25a red, but may wait until I can get the R72. Since it will be a once in a blue moon thing, I'll just get a cheapie off of Ebay rather than a Hoya. If I meter at ISO 12 without filter then add filter, what ISO do I tell the lab personnel that it was shot at??
     
  7. MattKing

    MattKing Subscriber

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    Ilford SFX is a 200 ISO film. It will give normal results when exposed without a filter under normal results and developed to a "standard" contrast.

    With any film, when you communicate with a lab about shooting speed, you are actually not talking about film speed at all.

    You are talking about what contrast you want them to develop the film to.

    So if you want them to increase the contrast of the film, you ask them to "push" the development.

    If you want them to decrease the contrast of the film, you ask them to "pull" the development.

    If you want the film to be developed to a standard contrast, you ask them for standard development.

    With other films, it is often helpful to increase contrast if one is forced to under-expose the film. So that is why people tend to associate "push" development with situations where the shots were metered at an EI higher than the "box" or ISO of the film. Pushing doesn't really add sensitivity to the film, but it does make underexposed film look marginally better.

    In my relatively limited experience with near IR films like SFX I've found that standard developing is most likely to work best, so that is what I would instruct your lab.

    The advice included here and elsewhere about the special metering one needs to do with near-IR films and filters like an R72 are essentially methods to deal with the fact that the filter blocks so much light, and the fact that our meters actually don't measure the near-IR light itself (just the visible light that accompanies it). The meter readings give us the ability to make a somewhat educated guess, but bracketing is still a good idea.

    None of the manipulations involving the Exposure Index you are using for metering really affect the development.
     
  8. kevs

    kevs Member

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    You should use the filter factor of the filter you're using to set your exposure meter by. If your filter requires a 2-stop exposure increase, you set your hand-held meter to ISO 50/18. You can check this by metering a scene then re-metering with the filter over the meter's sensor. If using a camera's TTL meter, set the meter to ISO 200/27; the meter will compensate automatically for the filter. I'd be more inclined to trust the hand-held meter; your mileage may vary.

    Whatever filter factor you use, you have the lab develop the film normally (ISO 200/27) unless you need to adjust the contrast.

    Some useful info here: http://en.wikipedia.org/wiki/Filter_factor

    Cheers,
    kevs
     
  9. seadrive

    seadrive Member

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    I just picked up a brand-new Hoya R72 for under $40 US, shipped, on eBay. Gotta love the free market! :smile:

    Shot my first roll of SFX 200 (120) yesterday, no filter. Looks pretty normal, rated it at EI 100, developed in my usual t-grain developer, Formulary BW-2.

    One strange thing I noticed is that, even with Photo-Flo treatment, this film beads water like crazy. My negs have water spots everywhere. I can't remember the last time I saw water spots on Photo-Flo-treated film. :confused:
     
  10. sly

    sly Subscriber

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    Makes me wonder about your photo-flo, as I have never noticed that with SFX.

    I recently pulled a blank roll of film from the developing tank. I had carefully measured and temperature adjusted the water, but had neglected to add the Rodinal I had sitting at the side of the sink. Been developing film for decades and never pulled that one before.
     
  11. pentaxuser

    pentaxuser Subscriber

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    Neither have I. I don't think there is any difference with SFX and any other Ilford film from a "beading" aspect. I too would look elsewhere for reasons why you experienced this problem

    pentaxuser