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Re: [PPLetterpress] Re: Exposure/washout units

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  • typetom@aol.com
    Thanks Gerald, Your description of the washout machine action is about as I imagined, having only seen one not in operation. My washout time is presently quite
    Message 1 of 14 , Oct 4, 2001
      Thanks Gerald,
      Your description of the washout machine action is about as I imagined, having
      only seen one not in operation. My washout time is presently quite a bit
      longer than others have mentioned, perhaps because I use a very soft brush
      and only very gently agitate. Obviously still some room for experimentation
      here, but my results now are quite consistent and it seems possible to
      control it by hand washing.

      My first question was probably simpler than your answer: just that the plate
      references (such as MK or MLD) don't tell me much unless I am using the same
      source for plates, I think. Would the MK152 be the same as the MS152 I get
      from Gene Becker? Maybe I just need to go back to the various notes Gene gave
      me to see if the answer is there. Similarly, I have had some difficulty
      making comparison with materials supplied by NA Graphics, because the names
      differ. So I thought it might help if I say Gene Becker's Miraclon MS152
      rather than 152 or MS152....

      Regarding toxicity, it sounds like it's a question of skin sensitivity rather
      than poison or carcinogin. I have hand-washed maybe 40 sheets (A3 size,
      297x420 mm = 11x15? cut to innumerable smaller plates) over six years or so.
      No gloves. No noticable skin reaction, no other problems at all (except an
      occasional cut from the sharp edge of the metal backing, of course). I do
      keep the water running slightly (to keep the temperature constant) so maybe
      the concentration is low. Or maybe I'm just not sensitive. So far, it seems
      to me remarkably benign. The very slight odor from unexposed material also
      seems inconsequential to me. UV light, of course, is bad for the eyes (and
      skin as well, I think).

      Best regards, Tom

      Tom Parson
      Now It's Up To You Publications
      157 S. Logan, Denver CO 80209
      (303) 777-8951
      http://members.aol.com/typetom
    • Frank Cabral
      Hello Tom, The orbital washout unit has been the only way I have been able to produce consistently good plates efficiently. The time factor is very important.
      Message 2 of 14 , Oct 4, 2001
        Hello Tom,
        The orbital washout unit has been the only way I have been able to produce
        consistently good plates efficiently. The time factor is very important.
        About twenty years ago, when the photo polymer was just entering the
        market, I was told by salesmen that the plate could be exposed in the sun
        and washed out in a sink with any brush. I spent what seemed and endless
        amount of time discovering only that there are many variables. I built
        things, converted things, nothing I did seemed to have the same results
        twice, or that the plates were just not good enough. I like process, but I
        was always off task trying to find a solution.
        While not quite a glorious epiphany, the machine allowed me to make
        accurate plates, in a short time with not so much guess work. I only had to
        pay attention to the orientation and density of the negative, the suction
        of the vacuum table, cleanliness of the kreene, monitor the wash out, water
        temperature, drying and final exposure to harden the material. The process
        is simple and consistent (generally).
        I like to examine the plate during washout to check that as much
        material has washed away as possible but not so much as to weaken its
        structural integrity , (small bits of the design, or letters that break off
        during printing that you don't notice until you are finished).
        Gerald has a good explanation of the washout process.
        I think Monotype had much more exacting details built into their
        production, and while success at times seems atmospheric the documentation
        they provided would allow you some success. There are just so many pieces
        to pull together and each one requires complete attention to detail.

        If you contact me off list I can send you some plate processing
        instructions for Miraclon/Rigilon, this is the MLD made by Toyoba. They
        also recommend it for crash printing, hot stamping and for pantograph
        masters. I have only used it for letterpress printing.

        Regards
        Frank
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