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Thread: PMK dilution vs. development time

  1. #1
    Tim Curry's Avatar
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    PMK dilution vs. development time

    Has anyone done a reduced dilution with PMK to increase development times? I need to extend times and am wondering about a dilution of 1:2:125 or 1:2:150. I will be trying it and wonder if there is any data. I've looked and can't find any reference to this specific question. Thanks, tim

    P.S. Just this question

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    PMK dilution vs. development time

    Tim,

    I've never heard of increasing the water content to extend times with this particular developer, but I suspect it would work to some degree. I have however read that decreasing the amount of part B lowers the activity of the developer. This recommendation (1+1+100) was for developing litho film to produce lower contrast continuous-tone images. Doing so would probably slow development enough so that you would have to extend times with normal films.

    I'm curious as to why you want a longer development time? With PMK I believe oxydation becomes an issue as development times become long.

  3. #3

    PMK dilution vs. development time

    Besides oxidation PMK is already fairly dilute. I've found with my materials that I actually need to extend dev time to achieve the proper contrast.

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    Tim Curry's Avatar
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    PMK dilution vs. development time

    Joe & Ron,

    Thanks for your replies and input. I'm playing around with azo and have found that a good negative for azo requires a film which is less contrasty than would be required for a "normal" grade 2 silver print. To compensate for this reduced contrast and full shadow detail, I've been increasing exposure and decreasing development times. I'm at the bottom end of development times now and still need to go with less time to get what I need (slow film speeds).

    For now, I'll try using a dilution of 1:2:125 and see where I end up. I have a sheet of 8x10 which I'm going to do tonight and will post a reply tomorrow to let you know. It is the second film. The first still shows too much contrast. Thanks, tim

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    Tim Curry's Avatar
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    PMK dilution vs. development time

    I decided to try 1:2:120 as a starting point and it did reduce contrast quite a bit. This seems to be the correct direction for what I'm doing so I'll continue along these lines. tim

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    PMK dilution vs. development time

    "Thanks for your replies and input. I'm playing around with azo and have found that a good negative for azo requires a film which is less contrasty than would be required for a "normal" grade 2 silver print. To compensate for this reduced contrast and full shadow detail, I've been increasing exposure and decreasing development times. I'm at the bottom end of development times now and still need to go with less time to get what I need (slow film speeds)."

    This seems very odd. Are you using AZO #2? The general consensus of AZO printers is that AZO 2 needs a negative that is much more contrasty than what one would require for a grade No. 2 silver paper. My own work with AZO #2 indicates that you need a negative with a DR of about 1.5, close to what you need for a Pt./Pd. print, or even more for the new paper. Wonder what is unusal about your situation?
    For discussion and information about carbon transfer please visit the carbon group at groups.io
    [url]https://groups.io/g/carbon

  7. #7
    Tim Curry's Avatar
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    PMK dilution vs. development time

    Sandy, in a nutshell, I have found that a "normal" film for enlarging paper prints with more contrast on grade 2 azo. Since this is the case, I've been increasing exposure and reducing development times to control contrast. Is this basic concept wrong?

    If I ever get what I need, I'll be glad to send along a film with two prints to let you see what my results are.

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    PMK dilution vs. development time

    Tim,

    I can not say that it is wrong in your case because if it works for you it must be right for you. But virtually everyone who prints with AZO has found the opposite, i.e. that you need a negative with a lot of contrast to overcome the inherent low contrast of AZO #2. Go to Michael and Paula Azo website to see some of the discussions on this issue.

    And, although I am not an expert AZO printer by any stretch of the imagination I have also found, in both my printing and testing, that it does indeed need a very high contrast negative, about 1.55 or so to print on the old AZO #2, and about 1.65 for the new AZO #2.

    So I think for sure there is some kind of anomaly in your experience.
    For discussion and information about carbon transfer please visit the carbon group at groups.io
    [url]https://groups.io/g/carbon

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