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Re: [PPLetterpress] Photopolymer with 'moving' parts

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  • Leslie Ross-Robertson
    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
    Message 1 of 12 , Dec 3, 2012
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      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

       

      Dear list members,

      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.

      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?

      The problem only happens with the '1' and the 'l' characters.

      I am in trouble, because it happens every time I try to process this work.

      Please, help!!!! :-)

      Thank you in advance and regards,

      --
      Lola

    • Harold Kyle
      ...and yet, it works! I know you and I have debated this in the past. :) I know that Boxcar Press would not be able to hold such fine detail without a short
      Message 2 of 12 , Dec 3, 2012
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        ...and yet, it works! I know you and I have debated this in the past. :)

        I know that Boxcar Press would not be able to hold such fine detail without a short back exposure. Our sales rep for Toyobo photopolymer plates, if I'm not mistaken, recommended it to us in the first place. It makes perfect sense to me why this would keep fine dots and lines firmly attached to the base of the plate. 

        But to each their own, and why add complexity if you're happy without?! 

        Thanks
        Harold


        On Mon, Dec 3, 2012 at 7:47 PM, Gerald Lange <Bieler@...> wrote:
        Rick

        Have you ever tried NOT back-exposing the KF95 since you were switched
        over? A portion of my clients use the KF95s and they come out just as
        well as the steel-backed version (which you cannot obviously
        back-expose.) Same processing times all around.

        Trying to think out the back-exposure thing, which, as a practice, does
        have to be done with liquid photopolymer, but is more of a hardening
        procedure for mounting though. Personally, the practice seems odd to me
        from a technical standpoint. With sheet photopolymer, the back-exposure
        has to go through the polyester backing, an adhesive layer, and get
        through the pre-existing back-exposure before it could have any effect.
        Can't quite see it.

        Gerald


        On 12/3/12 4:14 PM, letterpress_man wrote:
        > Gerald
        >
        > When Boxcar switched me to the KF95 about 3 years ago from another plate they told me the only differance was I needed to back expose it for 25 sec, been doing it all this time with great results on small type and fine lines.  The only time I had a problem was when the imagesetter messed up on some small lines because of an exposure setting.
        >
        >
        > Rick
        > --- In PPLetterpress@yahoogroups.com, Gerald Lange<Bieler@...>  wrote:
        >> Rick
        >>
        >> My understanding is that Boxcar recommends back-exposure only for the
        >> KF152 plate (the so called deep relief plate). Not the same animal as
        >> the KF95 or the steel-backs KM95/KM152, which all have harder ratings.
        >> Specs for letterpress plates generally seem to indicate hardness ratings
        >> around 67. This, combined with its thickness, seems to plague the KF152.
        >> There have been a number of reported problems relating to loss of detail
        >> and drift and the solution proffered has been back exposure. Though it
        >> too is back-exposed by the manufacturer. Most sheet photopolymer is
        >> back-exposed prior to backing.
        >>
        >> My A&V rep told me the KF152 plate was made for molding purposes and
        >> recommended I not buy it for letterpress. He never steered me wrong so I
        >> follow his advice. I had a client who actually needed a thick molding
        >> plate, a polyester-backed plate with a thickness of .100" (the KF152 is
        >> .60"). It is softer as well and, except for its insane cost and poor
        >> shelf life, it is perfect for metal clay work and similar.
        >>
        >> Gerald
        >>
        >>
        >> On 12/3/12 3:05 PM, letterpress_man wrote:
        >>> Lola
        >>>
        >>> I use the same plates as you are using, I buy them from Boxcar Press and they recomend 25 sec back exposure.  They sell and process probibly more plates than anyone one here so there advice should hold some weight.  I also agree with the other comments Gerald made.
        >>>
        >>> Rick
        >>>
        >>> --- In PPLetterpress@yahoogroups.com, Mª Dolores Jiménez Mondragón<doloresj3@>   wrote:
        >>>> Thank you Gerald for you advices. I will try to improve those parts of the
        >>>> process and I will be back with the results.
        >>>>
        >>>> Regards,
        >>>>
        >>>> Lola
        >>>>
        >>>>
        >>>> 2012/12/3 Gerald Lange<Bieler@>
        >>>>
        >>>>> Lola
        >>>>>
        >>>>> Your exposure time seems about right to me. But you really do need to
        >>>>> test the exposure time with a 21 steps grey scale. With a hardness
        >>>>> rating of 67 you should get a reading of 14-15 as solid—that means the
        >>>>> 14-15 boxes are not washed out or corroded (13 or below should be washed
        >>>>> out). Exposure times can vary dependent upon the condition of your
        >>>>> bulbs/ballasts. Fine lines or dots might need a slightly longer exposure
        >>>>> time.
        >>>>>
        >>>>> Basically, you are not giving enough time to build a decent structural
        >>>>> relief if your exposure/washout are out of sync and imaging is drifting.
        >>>>> You do not have to back-exposure this plate, the manufacturer has
        >>>>> already done that.
        >>>>>
        >>>>> You washout can vary quite a bit dependent upon bath temp, machine,
        >>>>> brushes, etc. Mainly you want a clean floor with no undercutting of the
        >>>>> surface imaging.
        >>>>>
        >>>>> Post exposure should be the same or longer than the main exposure. I
        >>>>> usually do about 1.5x.
        >>>>>
        >>>>> It is difficult to "read" the validity of a plate immediately after
        >>>>> washout because clinging moisture can cause optical distortion. Your
        >>>>> drying temp seems high. Specs sheet recommends 60-70 C. I'm not sure if
        >>>>> that is the problem but lower the temp and see if that helps.
        >>>>>
        >>>>> Gerald
        >>>>> http://BielerPress.blogspot.com
        >>>>>
        >>>>>
        >>>>>
        >>>>> On 12/3/12 1:58 PM, tinglado_letterpress wrote:
        >>>>>> Dear list members,
        >>>>>>
        >>>>>> 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.
        >>>>>> 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?
        >>>>>> The problem only happens with the '1' and the 'l' characters.
        >>>>>>
        >>>>>> I am in trouble, because it happens every time I try to process this
        >>>>> work.
        >>>>>> Please, help!!!! :-)
        >>>>>>
        >>>>>> Thank you in advance and regards,
        >>>>>>
        >
        >




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        --
        Boxcar Press
        509 W. Fayette St. #135
        Syracuse, NY  13204

      • Gerald Lange
        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
        Message 3 of 12 , Dec 4, 2012
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          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
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >  
          >
          >
          >
          >
          >
          >
          >
          >
          >
          > Dear list members,
          >
          >
          >
          > 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.
          >
          >
          >
          > 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?
          >
          >
          >
          > The problem only happens with the '1' and the 'l' characters.
          >
          >
          >
          > I am in trouble, because it happens every time I try to process this work.
          >
          >
          >
          > Please, help!!!! :-)
          >
          >
          >
          > Thank you in advance and regards,
          >
          >
          >
          > --
          >
          > Lola
          >
        • Leslie Ross-Robertson
          Hello Gerald: I completely agree! The less voodoo the better... Leslie ... From: Gerald Lange Subject: [PPLetterpress] Re: Photopolymer with
          Message 4 of 12 , Dec 4, 2012
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            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
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >  
            >
            >
            >
            >
            >
            >
            >
            >
            >
            > Dear list members,
            >
            >
            >
            > 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.
            >
            >
            >
            > 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?
            >
            >
            >
            > The problem only happens with the '1' and the 'l' characters.
            >
            >
            >
            > I am in trouble, because it happens every time I try to process this work.
            >
            >
            >
            > Please, help!!!! :-)
            >
            >
            >
            > Thank you in advance and regards,
            >
            >
            >
            > --
            >
            > Lola
            >

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