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  1. #1
    Eric Rose's Avatar
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    As many of you know, I abhor film testing. Generally I have had real good luck with going by the manufacturers recommendations and then fining tuning from there.

    It's not that I settle for less, I have had my negs evaluated by Les McLean and Bruce Barnbaum and both of them say they are great. In fact during the Bruce Barnbaum Black and White Workshop he made a point of getting everyone to come over and look at one of my negs on the light table to see what a good one looks like.

    One reason I feel I tend to stick closer to the manufactures recommended film speed is because I am a fanatic about keeping my meters calibrated. Must be my engineering background.

    I fail to see why some people get all bent out of shape trying to keep their exposures within 1/3 of a stop of what they consider ideal only to be using a meter that is out by close to a stop.

    You may say, well that's ok I tested with the meter I use and everything is grand. But do you check your meter for consistency? What's ok this week may be of whack next month due to meter drift.

    I use three meters. Not all at the same time, but as they came from the factory they is a stop and a third difference between them. Japanese meters are setup differently than European meters to begin with. Then you can introduce the usual deviation from factory specs on top of that.

    Initially what I did was pick one as my standard. This is the one that produced the negs I like to see. Then I noted on the other two meters what I had to bias their readings by. Not a very elegant solution to say the least.

    Fortunately I was able to pick up an ExpoDisk. Check it out at http://www.expodisc.com/ With this little disk I can calibrate each of my meters to a known reference.

    Since doing this I have completed a round of film speed testing on my favorite film APX 100 in 4x5 size. The eventual asa I came out with is very close to 85. That's only 1/3 of a stop from the suggested asa. I used HC110 Dil B.

    I have checked a few of my friends meters and in almost all cases they are out by close to 1 stop.

    I think much of the prevailing notion that you should in almost all cases half the asa of the b&w film you are using is due in large part to miscalibrated meters. Of course some people just think it makes them seem special, but that's another story. My comments only pertain to using regular developers such as HC110, Rodinal, Xtol and the like. Also it goes with out saying the asa determined was for N development.

    The major film manufacturers spend a lot of time and money using very fancy and well calibrated equipment to arrive at the asa's they do. Maybe if we used equipment that was calibrated a bit better we would end up agreeing with them more often.

    Another issue is shutter speed accuracy. When was the last time you got your shutters checked??

    Just my thoughts and ramblings. Your mileage may vary.

    Eric
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  2. #2

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    I think much of the prevailing notion that you should in almost all cases half the asa of the b&w film you are using is due in large part to miscalibrated meters. Of course some people just think it makes them seem special, but that's another story.

    The major film manufacturers spend a lot of time and money using very fancy and well calibrated equipment to arrive at the asa's they do. Maybe if we used equipment that was calibrated a bit better we would end up agreeing with them more often.



    Eric, I agree with you to a point. A part of the discrepency that exists between the manufacturers rated speeds and our actual EI's is that there is a difference in the manner that they measure the film speed and the manner in which we then meter the scene. From what I understand, Phil Davis covers this in his BTZS. Certainly meters can lose calibration.

    There are other factors involved here as well. For instance the developer used can have an effect. Additionally, ISO speed is not a fixed target. It is a moving target that varies in regard to development strategies. N+ will increase ISO speed while N- will decrease ISO speed.

    But apart from the additional factors that you didn't address, I do agree that to arbitrarily half the mfg rating is not always wise. When we get into the arena of greater density ranges above simple silver enlarging the proper film EI will make a big difference in the ability to achieve density ranges that Azo, Pt-pd, Carbon and others require. When we add into the mix the expanding of contrast the impact of improperly rated film becomes even more apparent.

    I think that your post was accurate so far as it went. I had heard of the disc before and I thank you for posting a link to their site. I may benefit from calibrating my meters.

  3. #3

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    Phil Davis in BTZS on gray card & metering (pp.113-116): " The idea of reading a gray card in the subject area ... makes some sense... Unfortunately, its the wrong shade of gray for general purposes." He goes on how the meter calibration & film speed ratings are wrong in being based on this so-called standard, whereas in fact they should be using a 12% gray card for metering. This translates into 1 stop off when doing in camera reflectance readings, incident reading or spot metering off a gray card.

    I try to follow his advice & increase exposure by 1 stop, that is when I'm not metering according to zone system. But I hope I understand him correctly (isn't the easiest of reads).
    van Huyck Photo
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  4. #4
    Joe Lipka's Avatar
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    The stickiest point to all this film and exposure testing (something that is done far too much by too many people) is the absolute very first step taken by the photographer. That is, identifying the zone.

    I spent the first two years of LF work doggedly pursuing Fred Picker's .01 above film base and fog. Lost two years of image making working that assumption.

    Once I gave up on that and started placing shadows on zones III and IV, everything went well.

    So to me, the reason behind the variation is the very first step. What does Zone III look like?
    Two New Projects! Light on China - 07/13/2014

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  5. #5

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    I spent the first two years of LF work doggedly pursuing Fred Picker's .01 above film base and fog. Lost two years of image making working that assumption.

    I thought that I was the only one that did that. Not only Fred (may his soul rest in peace) but also Ansel (who started it all as far as I can tell...and his soul also) propogated this. Never once telling us that Zone I placements are for dead people. As John Sexton once purportedly said "nothing lives on Zone III".

  6. #6
    L Gebhardt's Avatar
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    I am not going to say you are wrong, but I do find I need to rate most black and white films about 2/3 to a full stop less than the stated speed. This is to get good negatives for silver printing. It may be my meter, but my two Nikons agree with my Pentax Digital Spot. I get perfectly exposed slides (at rated speed) back from the Nikons as well, so they seem correct with color materials. My 4x5 transparencies are also properly exposed when I use the Pentax spot. So I don't know if it is the film or my meters, but for color the meters work, but for black and white they don't.

    My film testing is usually very limited and for speed consists of shooting a Kodak gray card at Zone I and seeing which speed gives me .1 of FB + Fog. I am actually in the middle of my first real film test where i am testing the developement times for the gamma, and then testing the speed for various times as well. I will then know if all this testing is worth the hours of tedious work (which I have grown to hate).

    Joe, what do you mean by:

    "I spent the first two years of LF work doggedly pursuing Fred Picker's .01 above film base and fog. Lost two years of image making working that assumption.

    Once I gave up on that and started placing shadows on zones III and IV, everything went well."

    I have never heard to place the shadows on zone 1, but rather to place the shadows on Zone III if you want the detail to print. Is this what you do now?

  7. #7
    Bruce Osgood's Avatar
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    I think the manufacturers box speed can be used for snap shots. Using the cameras average metering will get you average snaps. You won't go wrong if you are looking for average snap shots.

    I also think if you are trying to get greater shadow detail shooting at 1/2 the box speed will do that.

    Now, if you are trying to make an "expressive" negative you must do the film test with each camera shutter (not shutter speed) and find the .01 FB+F assigned as ZI by Adams. Regardless of film type (B/W), that is ZI. Once film speed is established, then it is time to find ZVIII (1.25-1.35 FB+F) by altering your development. Once found you have N speed and development.

  8. #8
    Eric Rose's Avatar
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    Well nice to see my photography has been reduced to "snaps" in one fell swoop.
    www.ericrose.com
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    "civility is not a sign of weakness" JFK

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  9. #9
    Leon's Avatar
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    regardless of who wrote what about which zone and where it should be placed on any scale, surely the whole point is about making your equipment and techniques work for you and give predictable results? If Eric's technique means that he stays with manufacturers speeds, then great, if mine are different, then great.

    It's only as important as someone wants to make it.

    However, I can only see two ways in being able to achieve this level predictability ... trial and error, or a short period of rigourous testing - both will have the required effect, but for me, testing is clearly the the most logical way of reaching this point.

  10. #10
    Joe Lipka's Avatar
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    There were two ideas colliding together in my post. Fred's holy grail (as I interpreted it ) was that Zone I was fb+f+.01. Once Zone I was established, then there was a regular progression beyond that point to establish placement of the other zones. For me using the fb+f+.01 gave me really thin negatives. On the plus side, I really learned how to dodge, burn, bleach, selectively develop, use Q-tips with hot developer and a whole host of printing tricks to get a decent looking print.

    The second idea is once I recognized where Zone III and IV were in the real world, I learned how to place them far enough up on the curve so that I didn't have to resort to every trick and dodge in the book to make decent print. Most modern films have a pretty long straight line section so you really have to work to hit the shoulder.

    The entire "secret" of the ZS is to be able to identify any Zone at ten paces and make a judgement on the correct exposure. I think correctly identifying any zone is the key to being a true "Zonista." Feel free to disagree, that's just the way I feel after thirty years of developing film.

    That being said, it's not the negative, it's the print. That's why we do this... Getting to a good print. There are lots of ways to get there. Enjoy your trip.
    Two New Projects! Light on China - 07/13/2014

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