Need help with film speed testing

Discussion in 'Large Format' started by tommy_mitchell, Jun 23, 2003.

  1. I apparently need help (insert your own joke here…….) with my film
    speed testing.

    I am returning of photography after a 10 year layoff. I am in the
    process of determining my personal film speed. I had previously
    used Tri-X in HC-100 which gave me a film speed of between 160 and
    200. I am presently testing both Tri-X and TMax 400 in D-76. I am
    testing with the method in Adams’ book The Negative and with the
    Zone VI/Calumet speed test instructions. (No, I’m not a masochist;
    I was hoping that by doing both of these, I could get my developing
    technique down and get a double check on the results to boot) The
    speeds that I am getting don’t seem reasonable to me. I am getting
    a speed of 320 to 400 for Tri-X and 400 to500 for TMAX 400. Based
    on my experience from years ago, these seems way too high to me.
    Also, a tour of this forum would indicate that these are not usual
    results.

    I am using a new Zone VI modified Pentax spot meter. I have
    repeated these tests using my Schneider 210mm lens and with my
    Schneider 150mm lens to account for possible quirky shutter speeds.
    I am reading the densities with an X-Rite 810 densitometer that I
    bought on eBay (yes, I have checked the calibration). I have sent
    one set of negatives to Calumet for testing, but they haven’t
    returned yet.

    Here’s my processing setup (although this shouldn’t really change
    the film speed test, or can it??):
    Jobo CPP-2 with Expert 3010 drum;
    D-76 at 7 min for Tri-X, 6 ½ min for TMax 400 (at 70 degrees);
    I use 800ml of developer for 10 sheets of film;
    Rotation of drum 50 rpm (checked per Jobo instructions).

    I’m really confused at this point. Are my results really different
    from everyone else’s? I didn’t think film speed testing was any big
    deal. I’ve done it in years past with several types of film without
    any problems. Digital is looking good right about now…….just
    kidding.

    Input from anyone and everyone is welcome.


    Tommy Mitchell
     
  2. It sounds to me like you are doing everything right. Until recently, I used Tri-X developed in trays with HC-110 and my EI was 125. I switched to an older Jobo CPE-2 and found that the EI increased. I now shoot HP5 and my EI 320. If I were you, I would go with the speed you have determined and now test for development times. I would go no further than N+/- 1 so you can start photographing and get some results that you can look at. You can go back to testing for N-2, etc., later.

    Don Wallace
     
  3. My EI for 4x5 Tri-X (4164) in HC110B, 20C, 5 minutes, Jobo CPP-2, 3010 drum is 400. With dilution H (AKA "half-B") I get an EI of 250 at 20C, 5 minutes.

    What you are seeing is the result of constant agitation. I personally have found HC110 (pick a dilution) to be uncontrollable with this setup - max. density too high. Another way to look at it is too much contrast. I've started several recent threads on this problem; the anwers might be interesting to you as you ramp up. Or not.

    I'm in the processes of testing XTOL as a replacement.
     
  4. Take some pictures. If you have good shadow detail, use the film speed your test indicate. if not, lower the film speed.
     
  5. There was a thread here within the last week or so started by someone who was using HC110, a Jobo processor, and Tri X (I think it was) film whose normal development times seemed inordinately short. Several people responded and as I recall said that Tri X, Jobo, and HC110 wasn't a good combination. If you do a search you should be able to find the thread, it may actually still be active, if not look in the archives.
     
  6. i have tested tmax 400 with d76 straight at 70 degrees, and gotten a film speed of 320. this is using tubes for processing. phil davis gets film speeds between 250 and 320 using d76 1:1. howard bond told me he shoots at 400 with d76 straight. i wouldn't worry, however, if you have done the tests satisfactorily, shoot some shots and evaluate the negatives. that is the true test.howard
     
  7. Everything you described about your test setup sounds reasonable.
    <p>
    What did you get for fb + f density?<br>
    Have you compared your spotmeter to another meter?<br>
    What exact shutter speed(s) and/or f-stops did you use for exposure?<br>
    What did you use for a target and light source?<br>
    Are you certain of the D-76 dilution?<br>
    Do you have the X-Rite calibration tablet or a Stouffer-type tablet to check your 810 calibration?<br>
     
  8. Testing is necessary but don't let it stop you from photographing. When I first started, I believed I had to have all testing nailed before I could make a good picture. Not!

    Sounds to me that your speed tests are pretty good. Go on to the dev test.

    Make some photos and take careful notes on the placement of the low values, then proper proof them. If your low values are proofing as you planned, your speed is ok.

    My experience has been that, no matter how carefully I test, I still need to always check my proofs, and often tweak my speed & dev time. If you are using your meter wisely, this will work. If not, nothing will work.
     
  9. Testting is a confluence of all the variables, I think your resutls are correct for your set up. Take into account that perhaps the meter is somewhat off and is actually giving you more exposure. Take a shot and see what comes out, if you got a good neg then those are the correct EI.
     
  10. Having read some of the other responses, I should have added that you really need to dilute HC-110 because of the constant agitation. The development times I specified in my earlier post were in Dilution E and I am thinking of going to Dilution F to lengthen my compression times. You need to make sure you have enough syrup in the mix and Michael Covington's web page on HC-110 is very useful in this regard.

    http://www.covingtoninnovations.com/hc110/

    Don Wallace
     
  11. Thanks to one and all for your very kind replies. Perhaps I’m not as far off as I had previously thought. Also, I had apparently not been clear enough in my initial post as to my present developer of choice. I had used HC-110 years ago, but haven’t used it with my new setup with the Jobo. I’m using D-76 now.

    To answer a few questions:

    My fb+f for Tri-X is 0.10 and for TMax 400 is 0.06
    I shot the test in open shade using a large black card
    No, I haven’t tested my meter against another one (don’t have another to test against, but would love to compare)
    I’m as certain as I can be about the D-76 dilution (it’s not diluted, straight from the stock bottle….not using a 1:1 dilution)

    I’m going to use the upcoming weekend and just take some photos. That will also give me some time to complete my development time testing. I’ll check the shadow density and make some adjustments as needed.

    Thanks again for everyone’s help and encouragement.


    Tommy Mitchell
     
  12. It sounds like you have covered all the bases, Tommy. The only other thing I can think of right now is possible bellows extention factor if the lense was focused significantly far from infinity when shooting your black card.

    Between the undiluted D-76, the agitation in the Jobo, and your meter, it may be that the speeds you determined are accurate.

    I'm not using D-76 these days in the 3010 drum. I use TMX, TMY, and Tri-X films but I develop them in Xtol. I shoot the TMX and TMY at published speeds and Tri-X at 250. I'm a bit surprised that you didn't get a lower value than your reported 320 to 400 for the Tri-X.

    I agree with your idea to shoot some pics.
     

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