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  1. #151

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    Bill, I didn't mean the SBR went that high, but rather that the film had a straight line that went that far - in other words, more lattitude. So if I had a high flare subject with say a 10 stop SBR, I could place the lowest values high enough on the curve (say zone V or VI) so that they would lie to the right of the portion of the curve most affected by flare. In other words all the subject values would be to the right of the portion of the curve where flare-induced local contrast compression is most pronounced.

    Obviously it was just hypothetical though, and only from the perspective of tonality, forgetting about the resolution and sharpness downsides to high exposure placements.

  2. #152
    Bill Burk's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    Bill, I didn't mean the SBR went that high, but rather that the film had a straight line that went that far - in other words, more lattitude. So if I had a high flare subject with say a 10 stop SBR, I could place the lowest values high enough on the curve (say zone V or VI) so that they would lie to the right of the portion of the curve most affected by flare. In other words all the subject values would be to the right of the portion of the curve where flare-induced local contrast compression is most pronounced.

    Obviously it was just hypothetical though, and only from the perspective of tonality, forgetting about the resolution and sharpness downsides to high exposure placements.
    I see what you mean. My curves don't go out that far. But the flare overlay isn't part of the film characteristics - it's part of the exposure. If you shift the exposure, you shift the flare.

    Steve has been talking about the idea that once you have a great range like 10 stop SBR, flare probably works in your favor by shortening the negative density range.

  3. #153

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    I'm going to have to sit down and think about this some more. If my hypothetical example is false I'm still missing something here.

    Also, as I said in an earlier response to Stephen's question regarding whether the flare is helping with a long SBR, I don't see why it is helpful, other than because you don't need to reduce development quite as much. It shortens the negative density range, but who cares about that if local contrast in the lower values is compressed?

  4. #154
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    Quote Originally Posted by Michael R 1974 View Post
    I'm going to have to sit down and think about this some more. If my hypothetical example is false I'm still missing something here.

    Also, as I said in an earlier response to Stephen's question regarding whether the flare is helping with a long SBR, I don't see why it is helpful, other than because you don't need to reduce development quite as much. It shortens the negative density range, but who cares about that if local contrast in the lower values is compressed?
    Right. It helps keep your negative able to print on paper. So in a sense it is working in a favorable direction. But flare doesn't necessarily improve the picture.

    Well. I am rethinking my position on whether flare hurts pictures. I've discarded a couple cameras with uncoated optics that gave me high-flare pictures. Now I appreciate the esthetics and have my regrets.

  5. #155

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    Quote Originally Posted by Bill Burk View Post
    Right. It helps keep your negative able to print on paper. So in a sense it is working in a favorable direction. But flare doesn't necessarily improve the picture.
    And this is once of the most important things most people miss, not only regarding flare, but regarding the negative and printing in general. All this stuff about fitting the negative range onto the paper, that doesn't make the difference between a crap print and a fine print at all.

  6. #156
    Stephen Benskin's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    And this is once of the most important things most people miss, not only regarding flare, but regarding the negative and printing in general. All this stuff about fitting the negative range onto the paper, that doesn't make the difference between a crap print and a fine print at all.
    It's just like owning a ton of expensive equipment doesn't guarantee a good photograph. They are simply tools. When I worked in a lab, people would call up and ask what film Herb Ritts or some other client shot. Like shooting the same film would make a difference.

    Also, as I said in an earlier response to Stephen's question regarding whether the flare is helping with a long SBR, I don't see why it is helpful, other than because you don't need to reduce development quite as much. It shortens the negative density range, but who cares about that if local contrast in the lower values is compressed?
    No one desires to have a lot of flare but there are some advantages when it is in moderation. There's a average flare today of around one stop, and before lens coatings, two stops. This encompasses the entire history of photography. Most people aren't even aware that any exists. So, it obviously isn't disastrous.

    Film speeds would be one stop slower without flare. For proof, simply look at the EI values that come from Zone System testing (no flare testing and not factoring in flare during speed determination), and ISO speeds.

    Now, we can compare the difference in effective film gradients between a film curve without flare and with flare and point out the compression of the tones from flare. But that doesn't tell the whole picture. It doesn't take certain other factors into consideration. Chief among them is what we perceive when we look at an image. I'm not talking about if a person can see the difference in tonal separation but what is considered a good print. Even if it were possible, an ideal print with a 1:1 tonal relationship with the original subject wouldn't be considered pleasing. In reality, camera flare reduces the shadow contrast and enlarger flare compresses the highlight, but that's okay, because as long as the mid-tones are printed slightly more contrasty than the mid-tones of the original subject, the resulting print is considered to have a certain level of quality.

    There are many more factors that are involved and considered including personal preferences, subject matter, and printing choices. But with careful testing a statistical model can be determined. Of course, it doesn't speak to the creative interpretation of a subject but about what generally will tend to yield more consistent high quality prints.

    In the example below, the two tone reproduction curves that will give potentially good subjective tone reproduction prints. One can be considered coming from the classic set of conditions, average luminance range, one stop flare, CI 0.56, and a paper LER 1.05. The other is from the same luminance range range, no flare, CI 0.47, and a paper LER of 0.98.

    Click image for larger version. 

Name:	Tone Reproduction Curve - flare and no flare.jpg 
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  7. #157

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    I'm going to have to go through your post carefully (and go back over some of the earlier ones too) over the weekend and make sure I'm getting it.

  8. #158
    Stephen Benskin's Avatar
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    My point is just that the film is only part of the photographic process. The tone reproduction curve in quadrant four takes into consideration paper, exposure, camera image, and the original scene. Below are the two complete tone reproduction diagrams that were use for the example in post #156. I'm going to post another example of a 9 stop luminance range with two stops flare a little later.

    Click image for larger version. 

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ID:	46842 Click image for larger version. 

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    Last edited by Stephen Benskin; 02-24-2012 at 06:44 PM. Click to view previous post history.

  9. #159
    Bill Burk's Avatar
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    Quote Originally Posted by Stephen Benskin View Post
    ...One can be considered coming from the classic set of conditions, average luminance range, one stop flare, CI 0.56, and a paper LER 1.05. The other is from the same luminance range range, no flare, CI 0.47, and a paper LER of 0.98.

    Click image for larger version. 

Name:	Tone Reproduction Curve - flare and no flare.jpg 
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    So I assume the "non-flare" curve is not realistic?

    I have been interested recently in the fourth quadrant curve of the "preferred" curve - that the 45-degree angle perfect curve is actually not attractive and there is a curve that is psychologically preferred. You may have shown that in recent posts? As I recall it is up and to the right of the 45-degree line but similar to your "normal" curve here. Is that right?

  10. #160
    Stephen Benskin's Avatar
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    Here are three more tone reproduction curve comparisons. They are:

    Comparing Film Processing Adjustment and Paper Contrast Adjustment
    LSLR: 2.70 (9 stops)
    Flare: 4.0 (2 stops)
    Exposure Range: 2.10

    Click image for larger version. 

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    Comparing Film Processing Adjustment and Film and Paper Adjustment with a No Flare Curve
    Exposure Range for 4.0 flare: 2.10
    Exposure Range for zero flare: 2.70

    Click image for larger version. 

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    Comparing Statistical Normal Conditions with Film Processing Adjustment Example
    Normal Conditions:
    LSLR: 2.20
    Flare: 2.0 (1 stop)
    Exposure Range (1.90)

    Film Adjustment Conditions:
    LSLR: 2.70 (2 stops)
    Flare: 4.0 (2 stops)
    Exposure Range (2.10)

    Click image for larger version. 

Name:	Normal and LSLR 9, 2 stops flare.jpg 
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    A few quick things to point out. Two stops of flare for a 9 stop scene is higher than normally is found with that luminance range, but it is not unusual. The two stops of flare brings the effective luminance range of the 9 stop scene down to a 7 stop scene at the film plane.

    As Normal processing is based on a 6 stop exposure range at the film plane, the film still requires reduced development, but not to the same degree. In this case minus one.

    In the third example, the primary difference in the shadow gradient comes more from compressing the 9 stop range down to fit onto the paper compare to the degree of processing required to fit the normal 7 1/3 stop range onto the paper.



 

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