I need help for Infrared problem

Discussion in 'Alternative Processes' started by moonwindrial, Jul 7, 2012.

  1. moonwindrial

    moonwindrial Member

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    hi. I'm Dongjoo Kim. student who studying photography in korea. I Plan to take a infrared photo in this summer vacation. today, I shoot first roll of my Rollei infrared 400 film. after develop, I found my flim is VERY transparent. Theres no image on the film. but the end of the film(Part of the film that came out from film magazine) is black. I think this means developer is worked. I don't know what's wrong. Can you help me?
    I use Rollei infrared 400 @ ISO 25, cheap infrared filter(massa IR 760), Minolta dynax7 body and Sony 24-70ZA. Developed 6min D-76(stock).
     
  2. MattKing

    MattKing Subscriber

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    Hello moonwindrial - welcome to APUG.

    I'm not sure the Rollei 400 has enough sensitivity to near-infra-red to permit use of an IR 760 filter.

    In my case, I have had most of my success with the Rollei 400 using an IR 720 filter and metering using a hand meter at EI 3 or EI 6.
     
  3. moonwindrial

    moonwindrial Member

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    Thanks for help, MattKing. I will try 720 filter.:smile:
     
  4. polyglot

    polyglot Member

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    How long were the exposures? With a 760nm filter, they would need to be very long indeed.

    I also use a 720nm filter (R72) but with Efke IR820. I shoot that at EI1, i.e. f/16 for 1s in full sun. Rollei 400 would probably work at about EI4 with an R72 (1/4s f/16 full sun).
     
  5. moonwindrial

    moonwindrial Member

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    Normal exposure(Metered without filter, E.I ISO 25) was F11, 1/15s. today was very sunny day. I took a photo at 1pm. I tried exposure bracketing. +3 stop ~ -3 stop. changed shutter speed only.
     
  6. Photocrack

    Photocrack Member

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    Rollei IR-400(S) is going down in sensitivity over 750nm rapidly. So you need a 715nm or 720nm IR filter. Then you have to expose around iso 6-12 depending on the IR circumstances.
    When using an IR760nm filter no bandwith is left for the film.

    The Efke IR820 is a bit more sensitive over 750nm. But the regular speed of this film is iso 100 only. When using above filters you have iso 1,5-3 left. Maybe with a 760nm filter and iso 0,5 you can have reasonable results.
     
  7. Arkasha

    Arkasha Member

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    Take a shot @ the box speed without any filters, just to test and see that all's well with your camera and processing.
     
  8. Andrew O'Neill

    Andrew O'Neill Subscriber

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    It's an exposure issue. You will need long exposures with that filter. Start with an EI (ISO) of 1.5. At f/11 on a sunny day, your exposure should be around 22 sec with reciprocity effect factored in. That's my experience, anyways. Keep good notes.