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Thread: Zone system testing method

  1. #1

    Zone system testing method

    I just bought my first 4x5 camera. I have been using the zone system with my 35 mm for 5 years now and am very familiar with it. I wanted to establish my perso nal ASA for Tmax 100 for the 4x5. I bought the film, loaded it, took a high con trast set of a few pictures of the downtown skyline. I placed the shade of a da rk building that still contained texture on zone III. I took a picture and brac keted as well 1/2 and one stop. I developed the film in TmaxRS and an unexposed sheet as well. I went into the darkroom and exposed a test strip with the unexposed sheet to fi nd my 'standard printing time'. When I expose the negative of downtown, the pri nt is completely white. I am now confused. I will repeat the process, but I am sure I did everything right. What would you do?

  2. #2

    Zone system testing method

    Dear Ray,

    Firstly, T-max can be a real headache. It's not a film for beginners (and I shou ld add that I'm still coming to grips with it). The reason is becasue its maximu m density is over 3.0; most films taper off at a maximum density of around 2.0, but T-max keeps on going. I don't know if you're familiar with characteristic cu rves and logarithmic density units, but that means that a T-max negative can be 10 times denser than an ordinary negative!

    So my guess is you've overdeveloped your negative, that's why its coming out fla t white. With a film like Tri-X that has a sloping shoulder the highlights would have blocked and the negative wouldn't have been too dense. But because of the long scale on T-max, if you overexpose or overdevelop it you wind up with a nega tive that's unprintable. (Let me know if you're not familiar with terms like sho ulder). So if I were you I'd halve your development time and start again.

    Also, are you using a prewash? I was using a prewash with Delta 100 and I just d iscovered you're not supposed to. It was causing me to overdevelop my negatives.

    Finally, you don't use the 'standard printing time' test for determining your AS A; that's for the development time. You determine your ASA by shooting bracketed frames of a dark surface you place on Zone I; the one that produces a density o f 0.10 above film base is the correct ASA.

    Let me know how you go.

    Andrew

    andrewherrick@hotmail.com

  3. #3

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    Zone system testing method

    I don't mean this answer to be flippant or sarcastic but I would buy or check ou t of a library any book that contains detailed instructions on how to perform th e film speed tests The method you used seems very rudimentary. Any number of pho tography books contain such instructions. A few that come to mind are Ansel Ada ms' book "The Negative," Fred Picker's book (the name of which I forget but he o nly wrote one), or "The Zone System Craft Book" by John Charles Woods. There are many others but these are three I am familiar with.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  4. #4

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    Re: Zone system testing method

    Don't forget the iris/shutter correction. Small apertures and high shutter speeds will present a problem.

    Also, shutters are not absolutely perfect in repetition, and batches of film vary too.

    Just down-rate the ISO about 2/3 stop and you'll be fine!

  5. #5

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    Re: Zone system testing method

    Quote Originally Posted by Andrew Herrick View Post
    Dear Ray,
    ............
    Also, are you using a prewash? I was using a prewash with Delta 100 and I just discovered you're not supposed to. It was causing me to overdevelop my negatives.
    Andrew: How does pre-wash cause you to overdevelop? If you do your tests always the same way, the washing 'effect' (if any) will automatically be taken into account. I started doing this decades ago.

  6. #6

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    Re: Zone system testing method

    This thread goes back to 1998, so a response isn't likely.

    Addressing the content, I've not heard of that strategy for establishing ASA for a film. Typically, when one brackets to determine ASA, it's half stops, not 1.5 at a time. And, it doesn't make sense to determine ASA with Zone III exposures. There's too many things wrong the OP's approach to waste time critiquing.

    The best way to determine film ASA (in my view) is to use Ansel Adams technique with a densitometer, which is to find the ASA that renders a Zone I exposure as 0.1 density units above film base plus fog. (In his early description of this method, Adams recommended between 0.07 and 0.15 density units.) Develop the film at the manufacturer's recommended develop time and temperature.

    When I do this with ASA 400 black and white film, I invariably establish the ASA as close to 1/2 the manufacturer's recommended ASA, which would be about ASA 200. Use this ASA to expose and process films using Zone System methodology, which sums up to exposing for the shadows (Zone III) and developing for the highlights (Zone VII).

    I usually think of manufacturer's recommended ASA's as being "suitable" for generic overall exposure readings when photographing, and when processing the film at the manufacturer's recommended time and temperature. (Blaaah; pinch nose and breathe through mouth.)

  7. #7

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    Re: Zone system testing method

    Quote Originally Posted by neil poulsen View Post
    This thread goes back to 1998, so a response isn't likely.

    Addressing the content, I've not heard of that strategy for establishing ASA for a film. Typically, when one brackets to determine ASA, it's half stops, not 1.5 at a time. And, it doesn't make sense to determine ASA with Zone III exposures. There's too many things wrong the OP's approach to waste time critiquing.

    The best way to determine film ASA is to use Ansel Adams technique with a densitometer, which is to find the ASA that renders a Zone I exposure as 0.1 density units above film base plus fog. (In his early description of this method, Adams recommended between 0.07 and 0.15 density units.) Develop the film at the manufacturer's recommended develop time and temperature.

    When I do this with ASA 400 black and white film, I invariably establish the ASA as close to 1/2 the manufacturer's recommended ASA, which would be about ASA 200.
    I use 35mm, and I find the same to be true across the board. The revision to the ASA speeds that occurred in 1960 was unneeded. The speeds in use at that time were based on the cameras, films, and processing techniques that had been in use for decades. For the most part, these were roll-film cameras with leaf shutters. The films were generally contact-printed. I remember seeing B&W photos of my relatives from the 1940s and 1950s, in smallish formats that had to be contact prints (from photofinishers). They were probably made on Velox paper. Leaf shutters tend to give more exposure than focal-plane shutters when the lenses are stopped down more than half-way. Shortly after 1960, 35mm SLRs with focal-plane shutters became popular, and these gave less exposure to the film at small apertures, and 3x prints, rather than contact prints, became the norm for photo-finishing.

    There was no problem with the exposure, rather it was the development that was excessive for 35mm films.

    In other words, using half ISO speeds is generally going to give optimum results.

  8. #8

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    Re: Zone system testing method

    ASA or ISO is established by the manufacturer and can not be changed. What you are trying to do s establish a personal exposure index.

  9. #9

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    Re: Zone system testing method

    Please consider reading "Beyond the Zone System" by Phil Davis. It will make your life so much easier and provide a technical vocabulary that will assist you in large format work.

    Brian

  10. #10

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    Re: Zone system testing method

    Quote Originally Posted by Jim Noel View Post
    ASA or ISO is established by the manufacturer and can not be changed. What you are trying to do s establish a personal exposure index.
    I'm finding the ASA that's optimum for the method that I use to expose and process film.

    Bear in mind that, stated ASA values can have a substantial impact on potential customers' decision whether or not to purchase a film.

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