Forte Polywarmtone Plus RC ISO P and R

Discussion in 'B&W: Film, Paper, Chemistry' started by mwdake, Feb 9, 2008.

  1. mwdake

    mwdake Member

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    I just bought a box of Forte Polywarmtone Plus RC before it is all gone.

    Does anybody know the ISO P and R values for this paper?
    The data sheet just tells me it is ISO P of 160.
    I am interested if anybody has insight in to the P and R values at different grades.

    thanks in advance
     
  2. fschifano

    fschifano Member

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    That will really depend on your light source and filtration. When I rebuilt the light mixing box in my Chromega II Dichro head, I had to recalibrate everything. Exposures were faster, and contrast was higher for a given filter setting or discreet VC filter from either Kodak or Ilford. Reason? The interior of the mixing box had yellowed from heat and age, lowering overall contrast and apparent speed.

    So you'll really need to figure that one out for your setup. Paper speeds, just like any other sensitized material, are figured with exposure to a known and hopefully standardized light source. Yours may not, and probably doesn't, match the one used for calibration.
     
  3. mwdake

    mwdake Member

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    fschifano

    Thanks for that answer.
    You are right I really need to do a calibration for this paper and my set up; that's going to be my next step.
    I was just hoping someone had some starting numbers for me to get me in the ball park before I dig deeper.

    Once again thanks for the post.
     
  4. ath

    ath Member

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  5. mwdake

    mwdake Member

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    Andreas
    Thanks for that link, this perfect.
    I use a RH Designs Zonemaster II, so these are exactly the numbers I was looking for.
    I can plug these in as my starting point and calibrate from there.

    regards

    Martin
     
  6. ath

    ath Member

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    Martin, I have calibrated Polywarmtone RC glossy on my Zonemaster 2 for a condensor head and colour head (both from LPL). If you want, I can post the values here; they should be better starting points for you.
     
  7. mwdake

    mwdake Member

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    Wow Andreas, that would be great.
    I am using Omega, both a condensor and Dichroic.

    Your values will be a better starting point for me, so please do post.

    Nice to meet a fellow Zonemaster II user, what do you think of it?
    I love mine as it saves me so much time as I don't usually have that much time when I do my printing sessions.
    For my Ilford and Kentemere papers it is nearly always spot on.

    regards

    Martin
     
  8. ath

    ath Member

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    Hello Martin,

    I'm very satisfied with my Zonemaster. There are some limitations (e.g. I had landscapes in 30*40cm where the black parts were too small to measure them with the probe) but once you have learned how it works it speeds up quite a bit.

    Now for the calibration.
    The first set is for my LPL (6*7cm) with condensor, newest Ilford MG Filters for filter drawer placed UNDER the lens:
    Grade offset ISO-R
    00 24 169
    0 26 135
    1 26 105
    2 25 89
    3 20 89
    4 11 89
    5 3 89

    The paper was quite fresh with this caliobration; maybe the ISO-R for the hard gradations is a bit off.

    The second set is for my LPL (6*7cm) with colour head (diffusion; no condensors), filter values according to the RH calibration manual (Kodak values for LPL):
    Grade offset ISO-R
    00 17 200
    0 15 172
    1 13 159
    2 16 138
    3 19 100
    4 8 86
    5 0 86

    For this calibration I put the bright value a bit nearer to white and the dark value nearer to black compared to the suggested values by RH.
    This last calibration is very fresh and not tested in real life yet.
     
  9. mwdake

    mwdake Member

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    Thanks Andreas.

    I really appreciate it.

    regards

    Martin