Photographing a Transmission Target for Ralph Lambrecht's Zone System Test

Discussion in 'B&W: Film, Paper, Chemistry' started by Rafal Lukawiecki, Jun 19, 2012.

  1. Rafal Lukawiecki

    Rafal Lukawiecki Subscriber

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    I would like to try Ralph's testing procedure, described in the 2nd edition of Way Beyond Monochrome, pages 217-224. I am not sure what is the best/sensible/easy way to photograph a Stouffer transmission target for this test. I will be using my 4x5 camera, in what is likely to be a 1:1 scale, or close to it.

    Ralf suggests using a slide duplicator (I don't have one), or placing the target on a light table. However he also suggests using the type of light that one normally uses for their photography. Most of my photography is landscape, so I suppose I should use daylight and not the CFL light of my light table. I guess I would need to construct a temporary light table from some milky plexi, and perhaps a reflective white sheet behind it, hoping for a cloudy day (well, in Ireland this one is pretty much guaranteed, it seems, except for today). The target would be placed on this plexi, and then I would have to shield the contraption, somehow, from any reflected light, so that it was functioning as a transmission tablet.

    Is that a correct way to approach it? Could I simplify somehow? Is this what others have done, who have attempted his testing procedure? I'd be grateful for any suggestions.

    Many thanks,
    Rafal
     
  2. Michael R 1974

    Michael R 1974 Subscriber

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    Why wouldn't one photograph a reflection target? Based on what you're describing, and another current thread my view is people make this stuff too complicated and the testing conditions, theoretical values etc become too far removed from actual field conditions for the attempted level of "precision" to translate to actual photography. Things like flare get in the way. Not to mention these tests do not typically yield a full H&D curve that plots out to high densities.
     
    Last edited by a moderator: Jun 19, 2012
  3. Nick Kanellos

    Nick Kanellos Subscriber

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    So here's what I do.

    • Insert the film into the 4x5 holder.
    • Insert the step tablet over top.
    • Turn on your light table.
    • Take a meter reading off the light table.
    • Add 4 stops. Set the shutter/aperture.
    • Focus your camera to infinity.
    • Add a filter or filter adapter ring to the lens, and ** gently ** lay the camera lens down onto the light table. (yep that's what I do.)
    • Take the photograph.
    • Repeat.
     
  4. CPorter

    CPorter Member

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    I contact the film as in Nick's suggestion but I photograph a white matboard in the shade, lens set to inifinity, the film exposed to +4 or +5. I don't suggest letting sunlight strike the target.
     
  5. RalphLambrecht

    RalphLambrecht Subscriber

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    why noy just tape it to a window?
     
  6. RalphLambrecht

    RalphLambrecht Subscriber

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    whoever wants to contzcr me directly, don't forget, i can also be reached on skype,under 'ralph lambrecht' or the email addreass below.
     
  7. Rafal Lukawiecki

    Rafal Lukawiecki Subscriber

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    Thanks for suggesting this, Ralph, and for responding to my question, I appreciate it.

    Wouldn't it be necessary to eliminate the reflections from the surface of the tablet when taped to a window (or to a milky plexi)? Similar to Michael's question, I am not quite sure why the procedure suggests the use of a transmission target, as opposed to a reflection one. I suspect it is easier to make transmission work accurately than dealing with different types of reflections, but I would love to know your thinking about this a little more. In any case, taping a tablet to a window would still leave an element of reflected light in play, unless the tablet-to-lens path was somehow shielded. I realise that those reflections would be a good few stops less than the transmissions, but wouldn't they matter?

    I think I understand why it is necessary to have the entire optical system in use, lens, bellows etc, so as to account for the flare, shutter behaviour, aperture etc, while performing the test. I wonder if having the tablet sandwiched to the film, as Nick and Chuck mentioned, would make a significant difference to the results.

    Ralph, you are very generous suggesting that I contact you by email or Skype. If you don't mind, I would like to take you up on this offer, especially when I have run the tests, perhaps in the next two weeks. I am about to order a densitometer today—I've never had one in the years I've been printing... Time to get that experience under my belt. "Way Beyond Monochrome" is an amazing compendium of knowledge, supported by logic, and it has awoken my desire to rethink and to question many of my habits. There is nothing else approaching the scope and the detail of your and Chris's book on the market, nowadays.
     
  8. Michael R 1974

    Michael R 1974 Subscriber

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    Rafal - a note of caution if I may.

    A densitometer is a useful tool, but make sure you don't become overly reliant on it when you test your materials. It should go hand in hand with actual printing tests. It is easy to get caught up in densitometer results, only to find in actual photography you're not getting what you wanted - or what you thought you wanted. I've seen this happen to people when they acquire a densitometer and start systematically determining their films speeds, development times for N, N-, N+ etc all based on theory and generally accepted target ranges (example - find a development time that gives a zone VIII net density of 1.2). Then they start making actual negatives and printing them, and find they are not getting the results they expected or wanted.

    Don't misunderstand me - I own a densitometer and I'm glad I have it. But, make sure you combine densitometry testing with "field" testing. Test your densitometry results by applying them to photographs, and make prints. Target density values can be good guidelines, but they are far from absolute. One person's N might be another person's N-1, etc.

    Michael
     
  9. Rafal Lukawiecki

    Rafal Lukawiecki Subscriber

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    Thank you, Michael, for the wise advice. I approach the testing, and the purchase of a densitometer, with a purpose. I've been printing for over 30 years, but with a more serious regularity, and in LF, only for just over 10. Over this last period, I noticed that I would like to get more shadow detail than I was getting, in high contrast scenarios, and that I would like to have more control over the appearance of highlights without having to traverse paper grades from 2 to 4.

    I am also on a quest to wean myself off split-grade printing, which has worked well for me—I have managed to get 24 pieces into a successful exhibition thanks to that technique—but which is now a crutch I want to let go, so as to simplify my dodging and burning, partly a function of the benefits but also complexity of Ilford 500H head. I have also missed the metronome for far too long...

    Though I usually print at 2.5, I have, I think, too many grade 3, 3.5, 1.5, and an odd few even grade 4 prints. Mind it, the subjects I photograph, and the way I want them printed, tend to have their contrast ranges a bit all over the place, and I am still learning how to control it. All these years I have been using box speeds and the Massive Dev Chart timings, plus 40% for N+1, and perhaps -30% for N-1. Last year, after I attended John Sexton's wonderful workshop, I have started to cut the speed of films I used. The dev times had to be cut too, but now there was less data as to how to do it—Dev Chart provides too many answers for these cases. Still, this has made my negatives much easier to print!

    What I would like to do now, is to formalise the times and speeds, hence the adventure into densitometerland. I hope this gives some context to my question. Besides, all of you guys seem to have enjoyed that adventure... Off to run some evenness of development tests now...
     
  10. Bill Burk

    Bill Burk Subscriber

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    A reflection target can only send a limited range of illumination back to the camera - something like 3% to 95% reflection. A transmission scale can send a much wider range of light because you are shooting the light through logarithmically small dark patches that can be a hundredth of a percent or less. With reflection, you get a few percent of the bright light in your darkest patch.

    Testing using a reflection target is possible, but you tackle the problem with a different approach. You take several shots per test series shooting something like a gray card, altering the amount of light hitting the film - one step at a time - by varying the shutter speed and f/stop. It's a lot more work for full film curve testing, but good for speed point tests.

    Sekonic makes a reflection target design with an 18% gray patch closely surrounding with patches reflecting plus and minus 1/6, 2/6, 3/6 stop. You might be able to find speed point faster with this target than you would with a standard gray card.
     
  11. Bill Burk

    Bill Burk Subscriber

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    Hi Rafal Lukawiecki,

    Looking forward to your test results and how you interpret them. I'd recommend picking up a box of a single grade of paper.

    Use multigrade paper when you have to and use the fixed grade when you a negative is good for it.

    At first, the box of fixed grade paper will sit mostly unused. Soon enough, you will start going through the box of single grade paper faster.
     
  12. Rafal Lukawiecki

    Rafal Lukawiecki Subscriber

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    Thank you, Bill, for the explanation regarding a reflectance target, and for the kind wishes of ever needing just a one, single grade of paper. I hope I can get to that point at some stage, again. Again, because that's how I used to print 30 years ago, not by choice, except I like my current results much more. :smile:

    At the moment, I enjoy the look of Ilford Multigrade Warmtone glossy fibre, processed in PF130 and Se toned, very much, so I am unlikely to change away from it. Also, while weaning myself off split-grade approach, I don't mind having the option of a very occasional burn-in with a different-grade.
     
  13. Michael R 1974

    Michael R 1974 Subscriber

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    Rafal - not sure why you are against using different grades of paper, split filtering etc. These are tools, not crutches. You mentioned John Sexton - who knows a thing or two about making good negatives. Yet, it is not uncommon for a single print to require all of the following:

    -Extensive burning/dodging and/or multiple grades
    -Flashing
    -Masking
    -Local bleaching

    Making good negatives is important, but I disagree with the notion the goal of testing should be to use a single paper grade. Particularly when high contrast lighting is involved, targeting specific paper grades can cost you.
     
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  15. Rafal Lukawiecki

    Rafal Lukawiecki Subscriber

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    Michael, I am not against any of these. They are wonderful tools, indeed, and I have greatly benfitted from them. I am trying to simplify everything I do as much as possible. I suppose it is a kind of a minimalistic quest in terms of the photographic process. For that reason, I wish to remove split-grade printing from it. It is a great technique, as I mentioned, I have to thank it for a successful exhibition, but I do not want to default on it at the moment, as I did for a few years. Also, as I mentioned in my reply to Bill, I am unlikely to move to single graded papers, but I would like to have enough control over my negative so that I could target a grade when I photograph a scene, rather than arrive at the grade only when printing. Perhaps it is an unnecessary goal in your and other's opinions, yet I would like to improve my craft to be able to do that.
     
  16. Michael R 1974

    Michael R 1974 Subscriber

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    Ok. Do post your results as Bill suggest above. I'm always curious. I must admit as much as technique is a means to an artistic end, I'm still a sucker for densitometry, a bit of a test data junkie I suppose... :smile:
     
  17. Bill Burk

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    Yes, I agree you don't need to carry the paper aim too far. I like doing it and can talk about it endlessly... But in a recent sidebar with CPorter, I see that Alan Ross develops his N+2 longer than I would, and he thus would need a flatter paper... but his highlights remain clean and separated, instead of shouldering off because of insufficient processing.
     
  18. Stephen Benskin

    Stephen Benskin Member

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    You really should consider eliminating as many variables as possible. The idea is to obtain good data and then incorporate all the variables, determined individually, when interpreting the data. If you are testing for the film's characteristics, you need to separate it from the optical system, and that means contacting.
     
  19. RalphLambrecht

    RalphLambrecht Subscriber

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    very true, but i find contacting difficult to do. that said i once made my self an adaptor to fit an lftaking lensto my enlarger,which alloed me to use it's shutterand expose filmcontacts from 1/250s to 1s .it worked wellwhen i used it to make msks for unsharpening.
     
  20. RalphLambrecht

    RalphLambrecht Subscriber

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    i have made myself a 4x5 slide holder now, but before my contraption , i just taped the step tablet tightly to a window and photographed it. as long as you taped it down nice and flat reflectionsare no issue. flare is almost eliminated by a black card board mask taped over it.
     
  21. Stephen Benskin

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    I'm also considering stuff like shutter efficiency, for example. Slower shutter speeds and small apertures are more efficient than faster shutter speeds and larger apertures. It's a simple question of the percentage of the exposure time the shutter covers the aperture. Here's a graph of it from Photographic Materials and Processes.

    Shutter Efficiency001.jpg

    Tests that use only a single exposure aren't as effected as doing a Zone System type test which consists of multiple exposures using different combinations of shutter speeds.

    Also, any optical system produces flare. Even if everything is masked off, flare will still be coming from the thinner steps on the tablet. Not only is there veiling flare, but local flare, where one step on the step tablet will influence the one next to it. Veiling flare will not only reduce what the results of the contrast testing, it will also increase apparent film speed. And since flare is hard (next to impossible) to measure, you can never adjust for it. It's always best to do a flare free test and factor in flare later. This is how the ISO standard for black and white film speed determination does it.

    This isn't all make of break kind of stuff. It's just something to consider when testing. Each variable has the potential to influence the test and the influence from multiple variables could be cumulative.
     
    Last edited by a moderator: Jun 21, 2012
  22. Bill Burk

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    I was under the impression that leaf shutters accommodated this by "not" being as fast as their highest speeds say they are.

    For example the 200th of a second speed setting might in actuality be 160th of a second real time to allow the sum of the bell-curve opening and closing over the full aperture... to be effectively 200th of a second.
     
  23. Stephen Benskin

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    That would be wonderful except it takes longer to expose the aperture if it is set at 5.6 than at 22. There's no way to fully compensate.
     
  24. RalphLambrecht

    RalphLambrecht Subscriber

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    i find it esier to printwhen y negatives are a bit on the soft side (n-1)and i compensate with a grade-3 paper as 'normal'
     
  25. Bill Burk

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    I'm about to find out, just started developing a "box" of N+2 negatives and I'm only developing them to N+1... So they are destined for Grade 3.
     
  26. Rafal Lukawiecki

    Rafal Lukawiecki Subscriber

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    Quick update. My densitometer is on its way, and Stouffers arrived today. I have also ordered a lab calibrated thermometer, as I really would love to know what is 20˚C, precisely. I realise that it does not matter that much, as long as I settled on some repeatably fixed temperature X within a shooting range of 20/68, but this gives me a chance to get one other variable a bit more fixed. So my testing is now delayed until week of 9th July. Will catch up on printing in the meantime.