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  1. #41

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    Quote Originally Posted by Stephen Benskin
    A somewhat relevant example is with the subcommittee on colorimetry in the 1930s. It took more than 6 years for them to agree color was a psychophysical phenomenon.
    I'm sure there were still some members of the commitee that disagreed!

  2. #42

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    Quote Originally Posted by Stephen Benskin
    Jorge my name is included with all the posts. It's Benskin. While I don't think "because everyone else is doing it" is a good argument, I am more than capable of coverting the BTZS terms, but I cannot personally use something I feel is incorrect. So please give me the same consideration and allow me the right to use the terminology I am most familiar with. Maybe we can both learn something new. Thanks.

    I cannot "place" units like meter/candle/second as well as log units


    BTZS mostly uses relative log-H if I'm not mistaken. Meter Candle Seconds is the antilog of log-H. Meter Candle Seconds are used in calculating film speed and, well, exposure, i.e. B&W film speed equation is 0.8 / Hm where Hm is in mcs.
    YOu can use whatever you want, you asked why we did not use the terminology you are using and I tried to respond.....no skin off my nose, I will simply ignore your responses because I dont understand them......just look at your last paragraph, you came up with the 0.8/Hm, where did you get that number? are supposed to take your word for it? And then I have to "see" the antilog of Log-H...sorry, just too difficult....
    I am sure that you are correct in citing this number, but it just makes discussing anything with you much more difficult.

    Sadly, once more this thread is widing down into another circle jerk. Instead of arousing the curiosity of the rest of the membership at APUG it is probably making them think we should stop wasting bandwidth and go take pictures...

    Since I am going to keep on using the "incorrect" BTZS nomenclature, I guess I have nothing else to add.

  3. #43

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    Quote Originally Posted by Jorge
    I dont know about anybody else here, but I cannot "place" units like meter/candle/second as well as log units.
    When figuring out exposure for step wedges with the enlarger, I prefer to use my incident meter with a flat diffuser. The owners manual then has a conversion table to "lux-seconds", these are the same units that Kodak often uses on their H&D curves. Converted to logs, of course.

  4. #44

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    Quote Originally Posted by Kirk Keyes
    I was trying to point out that, better explained with your equation, rearrainged a bit, that SBR=(ES/G).

    So I think what I was trying to say was "you have to state both ES and G to correlate it with SBR". (Thanks for reminding me of the formula.)
    I dont think you have to state both. Lets take jdef's example for instance, he developed HP5 to a G bar of 1.41....from that I can deduce the SBR for my system I simple have to plug in 1.45, In your case you would plug in 1.05 in jdef's case he uses 1.7 for ES. As I said, the G bar does not change.

    Let me just give you Phil's interpretation:

    In other words, assuming ES is constant, you can develop for either G or
    SBR. I prefer to target G, however, because it expresses the _relationship_
    between ES and SBR without requiring them to be defined specifically.

  5. #45

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    Quote Originally Posted by Jorge
    In other words, assuming ES is constant,
    Right - that's what I was trying to point out. When we are all using different materials, then it is not so clear unless we state the materials being used.

  6. #46
    Stephen Benskin's Avatar
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    I look at BTZS as tone reproduction with some Zone terms. I can accept however you want to apply it. I can also respectfully disagree with it too. We can argue that Davis writes that "SBR" is his abbreviation for Subject Luminance Range, but what's the point? I think it's possible to communicate our ideas without coming to an agreement on terms.

    I've place Naturalistic Photography for Students of the Arts on my reading list. Thanks for that.

    As for the question:
    Here's an interesting question. Except for special cirumstances, all scenes look best in a print when there is a full range of tones. Why can't we let a flat scene remain flat in the print (apart from artistic considerations)? It's flat in nature, why not the print?

    Part of the reason is psychological. It falls under the heading of visual adaptation, and more precisely the area of lateral adaptation, and perhaps falls within simultaneous contrast. Every photographer has experienced at one time or another photographing a scene on an overcast day and being disappoint by the flat results. The scene looked fine when photographing it. What happen? For various survival purposes, it's important to be able to distinguish elements in a scene as clearly as possible. So our brain wants to adjust every scene so that it has as full of a range as possible. That's why the scene looked good to the photographer and came out flat on the film. And I believe that is why we want to see a print with the full range of tones.

    Back to the topic of the thread. One of the images in the current issue of PHOTO Techniques required something new for me. The subject was the stone work in Peterborough Cathedral. The camera was pointed up toward the ceiling. Strong ambient light was coming in from a bank of windows and illuminating the lower columns, and the ceiling remained in shadows. The luminance range was around normal, but not only was the balance of tones not aesthetically pleasing, there was little tonal seperation in the stone work.

    If I pushed the film, the tones on the lower columns would be increased further unbalancing the tones, and the local contrast in the stone work would change little. Masking was an option. I figured it would take approximately four or five seperate mask to accomplish the look I wanted. I needed to hold down the columns while I brought up the ceiling. I needed to increase the local contrast over the entire image with an additional increase in the ceiling. There were a few touches that could also be accomplished by bleaching.

    I could either go the complicating masking route or try something different. I chose to go digital. Digital is just another tool. I had the negative scanned, worked on it in Photoshop (just using the tonal controls - no cutting and pasting) and then had it output on a negative. It now has the look I want and is almost capable of a straight silver print.
    Last edited by Stephen Benskin; 12-02-2007 at 12:32 AM. Click to view previous post history.

  7. #47
    Stephen Benskin's Avatar
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    Quote Originally Posted by Jorge
    YOu can use whatever you want, you asked why we did not use the terminology you are using and I tried to respond.....no skin off my nose, I will simply ignore your responses because I dont understand them......just look at your last paragraph, you came up with the 0.8/Hm, where did you get that number? are supposed to take your word for it?

    Sadly, once more this thread is widing down into another circle jerk. Instead of arousing the curiosity of the rest of the membership at APUG it is probably making them think we should stop wasting bandwidth and go take pictures...
    Why is everything a fight with you. You were the one to bring up using only BTZS. I replied why not real sensitometric terms. I then agreed that people shouldn't have to change the expressions they are comfortable in using. I can adjust to BTZS terms and I hope people can adjust to me. If you wish to ignore me, please do. I don't like to fight over everything.

    As for the equation, I said it is the B&W film speed equation. Why would I lie about that?

    As for the thread winding down, I believe I am the only person who has responded to the original question about different ways to deal with various luminance ranges. It's a potentially interesting subject if you would like to participate.

  8. #48

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    I have been watching this thread with interest. It seems to me that rather then dealing with differing scene luminance ranges it has once again degenerated into the usual discussion over the use of proper terminology.

    To that I say HO HUM....

    It seems to me that several who have a peliminary knowledge of BTZS have found that they want to re-interpert the terminology that system uses and to reinsert new terminology into that system.

    Now I have no problem with those who want to call something other then what the general mass of the users of that system utilize...so long as they don't expect the general mass to communicate to them with the ammended terminology...That desire would seem to be to be the height of arrogance.

    Interesting that with rather minor exceptions no one has really talked about dealing with differing luminance ranges. The one example given utilized digital process and I find that interesting.

    Now I will step aside...put a number of you back on my ignore list and wish you well.

  9. #49

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    Quote Originally Posted by Donald Miller
    It seems to me that several who have a peliminary knowledge of BTZS have found that they want to re-interpert the terminology that system uses and to reinsert new terminology into that system.
    Donald! Good to see you! Glad you made it.

    I think we are just trying to figure out how to fit the BTZS terminology into our world view.

    But anyway, it would be better to get back to Jay's original question.

  10. #50

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    Stephen Benskin wrote "Here's an interesting question. Except for special cirumstances, all scenes look best in a print when there is a full range of tones. Why can't we let a flat scene remain flat in the print (apart from artistic considerations)? It's flat in nature, why not the print?"



    While you would certainly be entitled to your viewpoint...I heartily disagree...
    A print can look stunning without the full range of tones provided there is adequate local contrast.

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