Is N+1 really necessary?

Discussion in 'B&W: Film, Paper, Chemistry' started by brian steinberger, Nov 24, 2011.

  1. brian steinberger

    brian steinberger Member

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    Say I have a low contrast scene where the shadow value falls on zone III and highlight on zone VI which I'd like to be zone VII in the final print. What differences in a final print would I see if I printed a neg with a range from zone III to VI (given N development) printing the highlight up to zone VII using a higher contrast filter vs. giving that negative N+1 development to bring it up to zone VII and printing with a normal contrast filter?

    My experiences have been that a lower contrast negative printed using a higher contrast filter gives more pleasing mid-tones, and highlights with more contrast than printing a neg given N+1 assuming there is adequate shadow detail. N+1 negs seem to have the mid-tones pulled up in value as well.

    Anyone have thoughts, suggestions on this?
     
  2. JLP

    JLP Subscriber

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    Yes and no! I think it depends on the scene you are photographing and also how you measure your light.
    If it is a foggy scene with no clearly defined subject i think your approach is good, leave it at about 4 or 5 zones on the film.
    If it is a scene with a a subject that you want to stand out i would suggest processing the negative with a +1 or +2 development time to get some micro contrast which i have a hard time getting if i don't develop the negative to more than 5 zones. I do always try to expand the grays as much as i can processing the film but i need to know where my highlights are when i expose the film so i don't blow them out in the processing stage.
     
  3. brian steinberger

    brian steinberger Member

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    Micro contrast is an interesting topic in itself. How is micro contrast enhanced differently by giving N+1 development vs. increasing contrast at the printing stage?
     
  4. nworth

    nworth Subscriber

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    By using N+1 development of the negative you mostly just achieve your objective of moving Zone VI to VII and pretty well leave alone the shadow values. Using a higher contrast filter expands the contrast of everything, possibly compromising the shadow values. I suspect the choice should be made in light of long experience with the materials used.
     
  5. ic-racer

    ic-racer Member

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    Unless you photograph extremes of light with very high or low contrast lenses, a single development time should be fine if you print with multigrade paper or you have a wide selection of paper grades.
     
  6. eddie

    eddie Subscriber

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    I'm not sure I can explain my experience well enough, but I'll try...

    This was something we explored while I was in college (1970's). In a very controlled studio environment, we exposed two sheets of film- one N, and one N+1. We printed to match the highlights, using a higher grade filter for the N exposure, lower for the N+1. There was a slight, but definite difference in the values of the midtones. The "higher" values in zone v lightened ever so slightly. I think it's easier to understand if you envision zone v not as an exact value, but as the range between the lightest zone iv value, and the darkest zone vi value. I'm not sure my explanation makes any sense but, put simply, if you stretch the tonal range of zone vi, there is some expansion of parts of zone v, too.
     
  7. JLP

    JLP Subscriber

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    In short i find it much easier to make prints if i have a negative with a large tonal range and as many zones as i can get safely in my negatives. It is easier to print " down" than up as far as i know but, i don't know it all so take it as what it is.
    I suggest that you go out and find a scene with similar ligthing and shoot one sheet or a roll each way and process accordingly. It's an interesting test and a good learning experience and does not cost very much.
     
  8. michael_r

    michael_r Subscriber

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    Brian, N+ is an interesting topic. There are several factors to consider, including film format and film type.

    Generally, both micro-contrast and graininess increase (graininess, rapidly so) with increased development. High micro contrast (essentially local contrast between very small areas of different density) tends to make it more difficult to maintain the most subtle highlight detail/separations. It is also "amplified" to some extent in the enlarging process, although this is generally less of a problem with today's films and diffusion enlarging helps too. Graininess, well that's obvious. It therefore follows the smaller the negative, the more pronounced these plus-development downsides. It is not something I would worry about with large format (unless the expansion is extreme), but with 35mm or medium format the negatives can outweigh the positives (to my eyes).

    Further compounding the issue with smaller formats is the fact we are often using tabular grain films in those sizes, and it has been argued tabular grained films in general have higher micro-contrast than "traditional" films. This is one reason many people prefer, particularly with tabular films, to downrate and cut back on development in general. That lowers micro-contrast, and softer negatives are also both sharper and finer grained (again, not an issue in large format). However the tabular-vs-traditional differences are less than they once were for two reasons, 1) current tabular films are better than they were in the beginning, 2) traditional films like FP4, Tri-X etc are more tabular than they once were.

    The other thing to keep in mind with most all of todays films is that in general, zone system controls are a little more tricky when trying to expand or contract macro contrast. In the zone system +/- heyday most of the films had more s-shaped curves. The low-to-mid values would move substantially less than the highlights. However most current films are short toe, straight lined films. So with expansions, more of the curve moves upward, which means the overall increase in contrast from shadows to highlights is lessened, while local contrast will tend increase along most of the curve, even down into the shadows. This can be thought of as more similar in effect to increasing the grade of paper or filter in the enlarging process.

    What I would normally suggest to people using small or medium format film and wanting maximum image quality with expansions, is to first chose a film that inherently has properties that most resemble what you need, and use development as a secondary control. So for example if you want more contrast, use PanF rather than say giving FP4 or HP5 plus development. Granted this is not always possible in the field.

    Incidentally, for small and medium format films, one way to reduce the increase in graininess for mild expansions up to N+1, is to selenium tone the negative. I find I can get ~N+1 with this technique and the increase in graininess seems to be visibly smaller than with N+1 development.

    Michael
     
    Last edited by a moderator: Nov 25, 2011
  9. CPorter

    CPorter Member

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  10. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    The shape of VC paper's HD curve changes as you change the contrast filtration. At low contrast grades the curve is bumpy and may have flat spots. At higher contrast grades the curve becomes much smoother.

    Because of this the look of a lower contrast negative printed with a higher contrast filter can look better than if the negative had been developed to a higher contrast and a lower contrast printing filter had been used.

    There is an application note on the Darkroom Automation web site that explains the source of the low-contrast VC paper problem:
    http://www.darkroomautomation.com/support/appnotevcworkings.pdf

    [It's the same app note that has been on the web site for a year or more. Please email me if this (or other) app note displays with a 'Star Trek' font on your computer.]
     
  11. doughowk

    doughowk Subscriber

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    David Kachel has an article on Local Contrast that provides an alternate viewpoint.
     
  12. brian steinberger

    brian steinberger Member

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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.
     
  13. 2F/2F

    2F/2F Member

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  15. Stephen Benskin

    Stephen Benskin Member

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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.
     
    Last edited by a moderator: Nov 25, 2011
  16. Dismayed

    Dismayed Member

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  17. pentaxuser

    pentaxuser Subscriber

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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
     
  18. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    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:
    [​IMG]

    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.
     

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    Last edited by a moderator: Nov 25, 2011
  19. lxdude

    lxdude Member

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    They are working fine for me, except the Butzi article's picture examples don't work.
     
  20. Stephen Benskin

    Stephen Benskin Member

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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.
     

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    Last edited by a moderator: Nov 25, 2011
  21. Doremus Scudder

    Doremus Scudder Member

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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
     
  22. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    Ive been printing for over 20 years and I'm still conflicted about the Zone system and shifting zones through development. I started printing during the 80s when multi-grade paper was pretty good. I worked for an old school photographer years ago that was using graded paper only. His philosophy was that MG paper was for photographers that didn't have their craft down. He told me that I always should "build" a negative for grade 2 paper. Sometimes when I shoot and process with a standardized time, I get negs that are so flat that I have to bump up the contrast to grades 3 or 4 to get the contrast I wanted. I heard of some photographers just use a standard percentage increase or decrease in processing time depending on how flat or contrasty the scene one is shooting. I like MG paper because I can have half grade increments when I print, where most graded paper are full grades. Another advantage is MG paper is being able to using many grades in a print. Reading Andrew Sanderson is an eye opener. http://www.thewebdarkroom.com/?p=479 I have great respect for the masters and their graded paper prints, but maybe don't be so tied to the Zone System? Everybody's thoughts are appreciated.
     
  23. CPorter

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  24. piu58

    piu58 Member

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  25. Doremus Scudder

    Doremus Scudder Member

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    Uwe,

    The Anchell quote was based on a printing technique of first finding the correct exposure for the highlights of the prints. If, then, the blacks are not "black enough," contrast should be increased by changing paper grade (or developer manipulations, etc.). I use this approach also, but with graded papers. This is the printing counterpart of "expose for the shadows, develop for the highlights." It is reversed for printing: "expose for the highlights (the least dense areas of the print, just like the shadows are the least dense areas of a negative) and adjust contrast for the shadows (the most dense areas of the print, like the highlights are the most dense areas of a negative).

    If you key on mid-tones when printing and then adjust contrast to get the snap you want in a print, then the Anchell statement doesn't apply. There is more than one way to skin a cat.

    Best,

    Doremus Scudder
    www.DoremusScudder.com
     
  26. Dismayed

    Dismayed Member

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