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Thread: Film speed test question

  1. #1

    Film speed test question

    Finally got around to starting my own testing using Ilford HP5 Plus, D76 and my Jobo. Using Steve Simmons method I shot the film at different speeds and found my minimum time for max black using Ilford glossy fibre paper using a grade 2 filter. At F:16 it was 22 secs.
    Tonight I will print the negs to find my EI, and tomorrow, using that EI, will shoot five more negatives to find my ideal developing time.
    Anyway, I have a lot of different papers available to me (I get good deals from local students who just graduated) but I think I read this testing is only good for the film / developer/paper I am using. If I want to print to Ilford RC glossy, do I need to repeat the process all over again?

  2. #2

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    Re: Film speed test question

    You should do the testing with the materials you intend to use for your final images. Each variable will impact the others. The experts suggest if you change film, film developer, paper or paper developer you should re-test.

    It all depends on how much quality (or lack thereof) you can tolerate in your images...

  3. #3

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    Re: Film speed test question

    I'm no expert, but have used this procedure to calibrate my ZS and you got it right: testing is only good for the film / developer/paper you're using

    and I may add to that: developer agitation regime for the negative and paper developer dilution/time.

    Unless you are willing to spend serious time testing different materials, I would stick to one paper, one film and work out the variables I mentioned.

  4. #4

    Re: Film speed test question

    I did the speed test with HP5 Plus 400 and, after doing the minimum time for max black thing, I found my EI was 400. Now my understanding is that the print should be a little less black than total black. It is more of a dark grey. The grey gets lighter from 400 to 320 to 200 and so on.
    When I exposed the film I metered an evenly lit surface and stopped down 4 stops, from 5.6 to 22 (I think thats what I did) putting the exposure on Zone 1. Is that correct? Do I need to re-do the test and stop down a little further? Thanks

  5. #5
    おせわに なります! Andrew O'Neill's Avatar
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    Re: Film speed test question

    Your zone I should barely be perceptable from zone 0 (film base). Is it? When I do an EI test, I go 4 stops less at whatever the box speed is. Make an exposure, then open up a third stop and make another exposure. Open up 2/3rds, and finally a stop. The correct EI is usally 2/3rds to a stop more exposure. I also use HP5 (developed in pyrocat-HD) and my EI is 250 for silver papers and 320 to 400 for alt processess. Because your prints of your test negs get lighter, means that you did things correctly. Each neg received a third stop more exposure. If EI 400 gives you your zone I, then your EI 200 neg is zone II.
    How did you determine that EI 400 is ideal for you, by the way?

  6. #6

    Re: Film speed test question

    So Andrew, if EI gives me zone I, I assume I use the 400 speed on my meter?

  7. #7

    Re: Film speed test question

    Quote Originally Posted by Andrew O'Neill View Post
    How did you determine that EI 400 is ideal for you, by the way?
    First I determined the minimum time for max black on Ilford Fiber Glossy paper. It was 20 secs.
    I metered an evenly lit surface and I think it was 125th at F/5.6 at 400 iso. I stopped down to F/22 and exposed. Did another at 60th sec, 30th and 8th which is the same I think as using iso 320, 200 and 100.
    I only exposed half of the negative.
    Once the negs were dried, I printed each one on the glossy paper at 20 secs. Once dry, the 400 iso negative/print was closest to black, but I cannot say it was barely perceptible, it was a vey dark grey bordering on black.

  8. #8
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    Re: Film speed test question

    I have a method that works with any materials.

    1. Take pictures
    2. Look at your negatives and prints
    3. If your negatives are too thin in the shadows or you can't print enough shadow detail, expose more

    Ta-Da! I just need a fancy name.

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