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13320Re: [PPLetterpress] Re: Photopolymer with 'moving' parts

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  • Leslie Ross-Robertson
    Dec 4, 2012
    • 0 Attachment
      Hello Gerald:

      I completely agree! The less voodoo the better...

      Leslie

      --- On Tue, 12/4/12, Gerald Lange <Bieler@...> wrote:

      From: Gerald Lange <Bieler@...>
      Subject: [PPLetterpress] Re: Photopolymer with 'moving' parts
      To: PPLetterpress@yahoogroups.com
      Date: Tuesday, December 4, 2012, 9:09 AM

       

      Hi Leslie

      Besides simply following manufacturer data for plate processing, I'd think that a lot of practices like this go a long way in helping to provide a modicum of regularly in producing successful plates.

      Warming up the area and raw stock to room temperature, running an initial false exposure (to heat the bulbs), as well as a false washout (to soften the brushes and distribute bath heat), waiting for the plates to cool down before post-exposure, etc., should result in consistent results throughout the day's work.

      It doesn't hurt at all to be fairly routine in maintenance of the machine: draining and flushing the bath religiously, keeping the bath clean of build up, lubrication, etc. Other practices should be regular monitoring of plate production for subtle changes, checking exposure rates of the bulbs and examining the bulbs (and ballasts) for inconsistencies, keeping the brush tufts stiff and straight and the brush plate free of hardened waste, replacing the Kreene at the first incident of possible problems from dirt or scratches or difficulty in quickly obtaining sure vacuum, etc., etc.

      There aren't really any special tricks to this, just a matter of keeping house, so to speak. And, it keeps the voodoo at bay.

      Gerald

      --- In PPLetterpress@yahoogroups.com, Leslie Ross-Robertson <modernoptic@...> wrote:
      >
      > Hello:
      >
      > At Otis we recently had a similar problem after changing the bulbs out on platemaker, the Anderson Vreeland Rep suggested warming up the bulbs for 5:00 cycles before making plates for a month or so until there is even burn on the bulbs. He checked and found uneven bulb strength when exposing. We have had no problem since, warming up the bulbs up first. We do not back expose... after a couple of months after the bulbs have an even burn it should not be necessary. Perhaps you need to warm up the bulbs? Also check temp on the wash out.
      >
      > Leslie
      > --- On Mon, 12/3/12, tinglado_letterpress <doloresj3@...> wrote:
      >
      > From: tinglado_letterpress <doloresj3@...>
      > Subject: [PPLetterpress] Photopolymer with 'moving' parts
      > To: PPLetterpress@yahoogroups.com
      > Date: Monday, December 3, 2012, 9:58 PM
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      > Dear list members,
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      > I am using KF95 PP, processing the plate as follows: exposure: 200 s, wash out: 240 s / 21 ºC, dry out: 10 min at 80 ºC and post exposure 300 s.
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      > The main problem is that some letters (body size 6 pt) are pushed out of its possition in the PP. Please, check this picture to see what I mean (http://flic.kr/p/dyigw8). I checked it after wash out and they seem to be at the correct position. Do you think that it could be something related to the dry out process? Do you think that a bit of back exposure could fix the exposed photopolymer to the plastic base?
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      > The problem only happens with the '1' and the 'l' characters.
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      > I am in trouble, because it happens every time I try to process this work.
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      > Please, help!!!! :-)
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      > Thank you in advance and regards,
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      > Lola
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