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  1. #11

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    David Kachel has an article on Local Contrast that provides an alternate viewpoint.
    van Huyck Photo
    "Progress is only a direction, and it's often the wrong direction"

  2. #12
    brian steinberger's Avatar
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    Thanks everyone for the replies. Good information here.

    David, interesting article. Seems there are some in both camps. One thing I have found that no one has mentioned yet is when I expose FP4 for N development I expose it at EI 100. If I expose at EI 100 for N+1 the mid-tones get pulled up too much, basically increasing the density of the entire negative. What I have done to correct this is expose directly in between 100 and 200 and develop for N+1. The results are much better. I know Ansel Adams mentioned the need for reduced exposure when giving N+1 development, but not many mention it. I remember taking a workshop in NYC back in 2006 and the instructor looked at me like I was crazy when I suggested reduced exposure with N+1 development. It tends to echo Michael's point of modern emulsions having more of a short toe, straight line curve where N+1 would pull more of the whole curve upward, which is what I'm experiencing. Reduced exposure seems to keep the low mids and shadows down after N+1 development.

  3. #13
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    [QUOTE=CPorter;1262621]
    Quote Originally Posted by brian steinberger View Post
    The only other thing I would comment on is that you said the shadow value "fell" on zone III and the highlight "fell" on zone VI----with black and white negative film, you base the camera exposure on the "placement" of the shadow on the gray scale in which case it's the highlight that "falls" on the grayscale relative to the shadow placement. All other luminances "fall" on the gray scale relative to the "placement" that is made in determining the camera exposure.
    The proper definitions of placement and fall are important. But the idea that shadows are the only thing that one may place in all cases is just wrong. You can place a metered subject on any zone, and let all the other tones fall around it. In practice it is usually lower tones that are placed, but not 100 percent of the time.
    2F/2F

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  4. #14
    Stephen Benskin's Avatar
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    I've attached a tone reproduction curve example. This curve represents how the print value's relate to the original scene's. One curve represents a 1.80 LSLR scene processed Normal and printed on a higher grade of paper (grade 3). The other curve represents a 1.80 LSLR scene processed N+1 and printed on a normal grade of paper (grade 2). In the top right hand corner of the curve are the gradients for each step. The N+1 curve has higher gradients in the mid-tonal range and the Grade 3 curve has higher gradients in higher tones.

    Both curves have higher mid-tone gradients than with a "normal" curve from a 2.1 LSLR processed normal and printed on a grade two. The straight line is a reference curve that represents the original scene. Any tones falling over the reference curve are darker than the original tones and any tones falling below the reference curve are lighter than the original scene. A preferred tone reproduction curve that "looks" like the original scene generally fall about 0.15 logs below the reference guide (except for the highlight). I've added a tone reproduction curve with a normal reproduction curve as a reference.
    Attached Thumbnails Attached Thumbnails Reproduction curve - Comparing N+1 and Grade 3 - with Normal reference.jpg   Reproduction curve - Comparing N+1 and Grade 3.jpg  
    Last edited by Stephen Benskin; 11-25-2011 at 04:49 PM. Click to view previous post history.

  5. #15

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    Paul Butzi ran some interesting tests before he went digital:

    http://web.archive.org/web/200812201...les/zoneVC.htm

  6. #16

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    I cannot get to the David Kachel link provided and the Paul Butzi link takes me to the Wayback Machine which simply seems to go round in a loop. The Butzi article is quoted but not opened.

    Anyone else having problems?

    pentaxuser

  7. #17
    Nicholas Lindan's Avatar
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    Quote Originally Posted by doughowk View Post
    David Kachel ... provides an alternate viewpoint.
    It's not an alternate viewpoint.

    There are several effects that need to be discussed:

    1. The effects of N+/-xxx film development
    2. The effects of idealized VC paper response w/ and w/o N+/-xxx film development
    3. The effects of the bumps, dips and flat spots in real-life VC paper HD curves
    4. The inability of VC paper to alter highlight and shadow contrast at the same time


    The Darkroom Automation application note addresses points 3 & 4.

    The problems with VC paper can be seen in the curves for MGIV WT:


    Several things are very clear:
    • There is a significant dip in contrast at 1.5 to 2.0 print OD for low contrast filtration
    • Almost all contrast change happens in the shadows when going from grade 00 to grade 2 1/2
    • Highlight contrast only changes in grades 3 to 5, at which time the shadow contrast remains mostly fixed

    The shape and location of bumps and dips in the HD curves changes with the specific emulsion and base. RC papers have different curves from FB.

    There are no subtle reasons for the differences in grade 0 and grade 3 prints [with negative development adjusted to hold a constant over-all contrast].

    Only trial and error with different combinations of development and paper grade will reveal the best combination for your particular case.

    The general statement can be made that variations in local contrast will decrease as paper grade increases. For some prints this may be good, for others bad.
    Attached Thumbnails Attached Thumbnails mgivfbwtd72hd.jpg  
    Last edited by Nicholas Lindan; 11-25-2011 at 10:40 PM. Click to view previous post history.
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  8. #18
    lxdude's Avatar
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    Quote Originally Posted by pentaxuser View Post
    I cannot get to the David Kachel link provided and the Paul Butzi link takes me to the Wayback Machine which simply seems to go round in a loop. The Butzi article is quoted but not opened.

    Anyone else having problems?

    pentaxuser
    They are working fine for me, except the Butzi article's picture examples don't work.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  9. #19
    Stephen Benskin's Avatar
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    The Butzi article is testing for something different than what the OP defined. Butzi is basically processing the film for different LSLRs, then matching the paper as opposed having one scene range which is shorter than a normal subject range, processing one N and printing on a higher grade or processing N+ and processing on a grade two. The attachment represents the results from a similar test as Butzi's.
    Attached Thumbnails Attached Thumbnails Reproduction Curve TMY G2 3 4.jpg  
    Last edited by Stephen Benskin; 11-25-2011 at 10:33 PM. Click to view previous post history.

  10. #20

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    My reading of the David Kachel article seem at odds with some of the views above, that is, unless I'm misunderstanding what is being said here.

    From what I understand, Kachel advocates using a higher paper grade when local contrast (micro-contrast) needs to be increased. In cases where the local contrast is not high enough, he even recommends contraction developments in conjunction with a higher paper grade. It's just the opposite for cases where local contrast needs to be decreased: overdevelop and then use a lower paper grade.

    FWIW, I've been doing this very thing for years, having read the Kachel articles long ago. I am convinced that he is correct. I often develop to "less than ideal" and then expand with paper grade in order to increase local contrast. The second case, overdeveloping and using a lower grade, I have found to be needed only rarely. Nevertheless, it is helpful when needed.

    From what I understand of the above, many of you are advocating using expansion development to increase local contrast. This seems to be the opposite of what Kachel recommends.

    Comments?

    Best,

    Doremus Scudder
    www.DoremusScudder.com

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