can developer affect contrast?

Discussion in 'Darkroom Developing and Printing' started by Mike, Dec 15, 2003.

  1. Mike

    Mike Guest

    I switched to Ilford Multigrade from Dektol because I like mixing concentrates better than powders, and it was
    competitively priced at my local shop.

    I'm not positive, but it _seems_ like I have to add more magenta to my light in order to get decent contrast. Is this
    possible or am I just drawing wrong conclusions from my observations (maybe my film developer is going bad or my
    thermometer, which I dropped, changed)

    My process isn't that fine-tuned...
     
    Mike, Dec 15, 2003
    #1
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  2. Mike

    Mike Guest

    After reading Richard's _excellent_ post on variable film development, I believe that either I'm not developing to
    completion or my negatives have changed, or its just my imagination ;)
     
    Mike, Dec 15, 2003
    #2
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  3. Paper developers should not noticeably affect contrast to any
    significant degree, if properly diluted and fresh, and at the proper
    temperature.
     
    Michael Scarpitti, Dec 15, 2003
    #3
  4. Mike

    Mike Guest

    Hmm...temparature. Thats a variable that has changed being that my basement has dropped from about 68 degrees to 62
    degrees due to winter setting in.
     
    Mike, Dec 16, 2003
    #4
  5. magenta to my light in order to get decent contrast. Is
    this
    being that my basement has dropped from about 68 degrees to
    62
    That could do it.
    For the most part developers don't affect paper contrast
    much. The well known variable contrast developers probably
    have a total range of about + or - half a grade.
    Paper contrast is defined by how much difference in
    exposure is needed to vary the density from none (paper
    white) to whatever the maximum for the paper, typically
    approaching Log D 2.0. Actually most paper will produce a
    deeper Dmax if its given grossly more exposure than is
    normal in printing, but this is never reached in normal
    printing.
    To a limited extent adjusting exposure and development
    will affect contrast a little, but, because of the nature of
    the paper emulsion underexposing and extended development
    will generate fog but not much increase in contrast, while
    increased exposure and shortened development will reduce
    contrast a little but may result in uneven development and a
    Dmax short of the the paper maximum, or rather, short of
    good blacks. Most of the difference in contrast in paper
    grades comes from the distribution of silver halide
    particals of different sensitivity. For high contrast paper
    (or film for that matter) the emulsion is made so that the
    sensitivities of the particals are close together. For low
    contrast the particals have a wide range of sensitivity.
    Since the developer can not affect this distribution it
    doesn't affect contrast by much.
    Now, we all know that very high contrast film can be used
    for pictorial purposes by using special developer. Kodak
    Technical Pan is such a film, basically a high contrast copy
    film, it can produce nice long scale negatives by using a
    special low activity Phenidone developer.
    I suspect that somewhat the same thing could be done for
    paper. I havent tried this. Perhaps someone with a good
    supply of D-23 could try it on paper. I am serious about
    this. I haven't the materials at hand at the moment and
    didn't think of trying it when I did :-(
     
    Richard Knoppow, Dec 16, 2003
    #5
  6. Mike

    Jim Phelps Guest

    To a certain degree, true. Most _normal_ developers will not change the
    contrast - much. But then again, there's many developers that work up to a
    paper grade softer in contrast. Tetenal Centrabrom-S and Selectol Soft come
    to mind.

    Ilford MG is a less active developer and requires a full two minutes for
    complete development. Dektol is more active and requires half this amount.
    If you don't take this into consideration when making the switch, then you
    may also see lower contrast.
     
    Jim Phelps, Dec 16, 2003
    #6
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