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  1. #61
    Photo Engineer's Avatar
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    I think you are both right. It is crude sensitometry and crude densitometry. You are taking very few points which you call zones and making them work for you in your exposures, but the curve has many many more points to measure and which can be very revealing to/for you.

    PE

  2. #62

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    Quote Originally Posted by Stephen Benskin View Post
    Ron, don't you mean crude sensitometry?

    Changing the subject again, I would like to go back to the idea of comparing overexposure examples. In the attachment, the data is from four tests. One with TX CI 0.56, exposed normally and overexposed. Printed for best print. The second two tests are with Del400, CI 0.57, also exposed normally and overexposed the same amount as the TX. The difference is that the DEL400 is beginning to shoulder off. The DEL400 is the film shown in Quad 2. The Gradient Guideline Comparison is set to show the resulting print RD. The two Guideline and Gradient Comparisons are a further breakdown Quad 3 results with the two Del400 tests. The use of the tone reproduction diagram gives me information that isn't obtainable from using the curves in isolation.

    Attachment 67375
    Whenever you have referred to your program I always pictured a series of spreadsheets, not an actual program. Impressive. This could be a powerful teaching tool (if more people were interested in learning about these things).

    I feel a need to "defend" Ansel a little bit (and I say that as someone who is actively studying/learning non-crude sensitometry), but perhaps in another thread.
    Last edited by Michael R 1974; 04-17-2013 at 08:28 PM. Click to view previous post history.

  3. #63
    Stephen Benskin's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    Whenever you have referred to your program I always pictured a series of spreadsheets, not an actual program. Impressive. This could be a powerful teaching tool (if more people were interested in learning about these things).
    Visual Basic. Not that impressive.

    Here's a screenshot of the main part. Click image for larger version. 

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    Have you been able to track down those Haist examples?
    Last edited by Stephen Benskin; 04-17-2013 at 08:59 PM. Click to view previous post history.

  4. #64

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    If you go back a few posts I think Ron was referring to the Sensitometry chapter at the end of Volume 1 (he posted a few examples). But there isn't really anything about tone reproduction.

  5. #65
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    Just found something interesting. In Kodak's publication G-1, Quality Enlarging with Kodak B/W Papers, they have a Dorst type reproduction diagram, but with a few changes from the one found in Kodak Professional Black-and-White Films. This one isn't fudged. It uses the statistically average luminance range. A luminance range of 2.20, not 2.10. Flare is 1 stop and is listed as "Moderate Flare Level Lens." The camera image has a illuminance range of 1.90. In Professional Films, the illuminance range is 1.85 and the flare was a little over 2/3 stop. They needed to do this to have the 2.10 subject luminance range calculate down to the CI 0.56, which both examples use.

    Click image for larger version. 

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    I know this doesn't exactly belong here, but also found this in Quality Enlarging. It appears that I'm not the only one who thinks the visual response to luminance levels is important.

    Click image for larger version. 

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    And to finish it off a Subjective Tone Reproduction diagram.

    Click image for larger version. 

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    Last edited by Stephen Benskin; 04-17-2013 at 10:11 PM. Click to view previous post history.

  6. #66
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    We used to use these in 3 colors to get an understanding of color reproduction. This is an old tool. Grant Haist showed monochrome reproduction (as did Mees). I have posted Haist's method above and Mees is in his Revised Edition for those interested.

    PE

  7. #67

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    Quote Originally Posted by Photo Engineer View Post
    I think you are both right. It is crude sensitometry and crude densitometry. You are taking very few points which you call zones and making them work for you in your exposures, but the curve has many many more points to measure and which can be very revealing to/for you.

    PE
    This very right. In 'The theory of the photographic process, 4 th edition' T.H.James this subject has been treated in detail. Nrelson in the tone reproduction , clarifies that zones are an approximation only ( crude). Elsewhere in the same book it has been shown that a tone as perceived by the human eye is not a simple thing like a zone; it will depend on the microstructure. A microstructure that will seen in modern photographic optics. But the human eye fails to see that. This called: ' Do not believe your eye'. The eye is misleading. A modern lens is not misleading. PE uses crude for this difference.
    All this is nothing new. Leonardo da Vinci knew already that de 'invisible' details are important. His brushstroke inthe Mona Lisa are hairthin and 2mm at a maximum.

    Jed

  8. #68
    Stephen Benskin's Avatar
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    Quote Originally Posted by Jed Freudenthal View Post
    In 'The theory of the photographic process, 4 th edition' T.H.James this subject has been treated in detail. Nrelson in the tone reproduction , clarifies that zones are an approximation only ( crude).
    Exactly, Zones are non specific. They are referrences which makes their use in quantifiable testing questionable. There's this line from Doctor Who where he's attempting to describe time travel, "People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint - it's more like a big ball of wibbly wobbly... timey wimey... stuff." How does one plot an "ish" with any precision?

    Seriously, I've always thought the using Munsell values to define the print Zones would be a good idea. Jack Holm has linked zones to he defines as
    Preferred Reproduction Density" for a print (reflection hardcopy).

    Click image for larger version. 

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    Notice Holm has two different columns for preferred reproduction densities for transparencies. That's because densities are perceived differently under different viewing conditions. The same as with prints. There's that subjective reproduction again.
    Last edited by Stephen Benskin; 04-18-2013 at 07:36 AM. Click to view previous post history.

  9. #69

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    Well, you're all going just a little bit too far. Sorry. You're characterizing the Zone System through the unfortunately poor re-writes, bastardizations, "additions" and "improvements" to Adams made over the years by people who want to sell books. I would also point out Adams seems to have been as aware of, and interested in subjective considerations as Stephen. Mees appears to have endorsed the Zone System as it originally existed. Finally, a careful reader of Adams will note he does not claim any of the transmission/reflection densities, Zones etc are absolutes. It is just an introduction to applied sensitometry, and all introductions and simplifications are 'crude'. They have to be, because most people are crude and have no interest in detailed learning.

  10. #70
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    I agree Michael.

    The drawing I started this thread with was meant to illustrate a simple concept & show a conceptual truth not necessarily a mathematically perfect model.

    It is an expression of Adams ZS, visualization of print idea, with alternative film exposure options, it is a way for me to visualize how I might or can make a negative to get me from a to b.

    Adams basic visualization concept is really strong in an artistic sense and easy for most to grasp, the details and measurements drag it around and beat it up because the more rigidly a system or idea gets defined, the more it becomes a one trick pony. Even Adams falls prey to this because of the subject matter he chose. If Karsh had written those books instead the world's perceptions of ZS principles might be very different.

    I try to remember that personally I'm not a machine taking pictures of documents or laboratory cultures, I'm a human taking pictures of humans and of emotions and of ideas
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Anaïs Nin



 

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