Plus and Minus Development Percentages

Discussion in 'B&W: Film, Paper, Chemistry' started by timbo10ca, Mar 4, 2008.

  1. timbo10ca

    timbo10ca Member

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    Stimulated by a couple of recent threads and some testing I've been doing, I'm just wondering what people are finding *in general* for N+1 N+2 N-1 and N-2 development, given as percentages of Normal. Do you find it depends highly on the developer, or do the percentages stay pretty much the same?

    Tim
     
  2. david b

    david b Member

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    I use 15% for traditional films and 10% for T-grain films.
     
  3. timbo10ca

    timbo10ca Member

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    That would be for +1 and -1? This is less than I would have expected.
     
  4. david b

    david b Member

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    yes +1 is 15% more development

    -1 is 15% less development
     
  5. Christopher Walrath

    Christopher Walrath Member

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    Most developer manufacturers will provide augmented development times for their film, such as Kodak's literature available on their website, but your getting some pretty good numbers here. It's mostly trial and personal preference after time.
     
  6. CPorter

    CPorter Member

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    Tim,

    My tests for 4x5 T-Max 100 shakes out as:

    N+1 = +25%
    N+2 = +44%

    N-1 = -12.5%
    N-2 = -31%

    I can't provide any insight to the second part of your question because I've only tested thoroughly with D-76 (1:1). I'll be doing some testing with Microdol-X sometime in the not too distant future. I've been reading that it has some pretty decent compensating affect with TMX.

    Chuck
     
  7. timbo10ca

    timbo10ca Member

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    Interesting- these are some pretty different numbers- close to what's recommended for the minusses but quite a bit more than the general recommendations for your plusses. And with a T-grain film too......

    Tim
     
  8. jeroldharter

    jeroldharter Member

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    I think that the percentage figures are rough numbers. Unless you do your own tests, everything is a rough approximation. I suggest that you use development times that are easy to remember and intuitive, e.g. times like 4 minutes, 5.8 minutes, 8 minutes, 11 minutes.

    I did TMAX 100 4x5 testing with TMAX 100 developer using the BTZS process with the results measured by the View Camera Store. My results in BTZS tubes at 75 degrees differed quite a bit from published numbers but seem consistent.

    For minus through normal development, I use TMAX RS developer at 1:9 dilution. For plus development I use 1:4 dilution. The processing times range from 4 minutes in dilute developer for minus development to as long as 16 minutes in stronger developer for plus development. I can range from about N-2 to N+2.

    Don't forget that film speed changes with development, in my case by a considerable degree. Film speed is slower with contracted development and higher with expanded development.
     
  9. smieglitz

    smieglitz Subscriber

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    Anyone else use dilution to push 'n pull?

    I used to use HC-110 at various dilutions and a set development time and temperature (6 minutes 20C). [Since I've gone more primitive (SF lenses and salt or vdb printing) most stuff gets dilution A or stronger to pop the contrast and increase the negative density range.]

    Anyone have contrast index or G-bar numbers for N, N+, etc.,? I should have some to compare in a couple days as I work through some tests.

    Joe
     
  10. fhovie

    fhovie Subscriber

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    I would have to go with Porters numbers - 10 and 15 percent has not worked for me - that is just the compensation for variations in temperature - not a significant density change - at least for developers that normally take 10 minutes to get to N
     
  11. Ian Grant

    Ian Grant Subscriber

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    Yes, I used to. With Rodinal and Tmax100 & APX100 I used 1+25 for N+2, 3+100 for N+1 & N, and 1+50 for N-1 & N-2

    With high dilution liquid developers, then varying the concentration seems to be a far better option, I also used this method with Ilfotech HC ) Ilfords version of HC110), and the first Tmax developer, before finally settling on Rodinal.

    Now using Pyrocat HD and Xtol my times are between Chuck's, and the other suggestions.

    N-2 -20%
    N-1 -15%
    N
    N+1 +20%
    N+2 +35%

    Ian
     
  12. Lee L

    Lee L Member

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    Here are a couple of threads on using varying dilutions of HC-110 to control contrast.

    http://www.apug.org/forums/forum37/12727-contrast-control-via-dilution.html
    http://www.apug.org/forums/forum37/23370-contrast-control-via-hc-110-dilution.html

    The info is from The Handbook for Contemporary Photography, 4th Edition by Arnold Gassan. 1977

    Lee
     
  13. jfish

    jfish Member

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    The basic general rule is +25% increase in time per stop, and -20% for pull per stop. Your agitation, exposure and preferences will dictate the final amount.