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Re: Photopolymer separating from polyester backer

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  • bielerpr
    Glenwood Sounding more like you have an exposure problem than photopolymer separating from the backing? Might be best to be very specific as to the problem. Go
    Message 1 of 22 , Aug 1, 2010
    • 0 Attachment
      Glenwood

      Sounding more like you have an exposure problem than photopolymer separating from the backing? Might be best to be very specific as to the problem.

      Go here to get lamps:

      http://www.atlantalightbulbs.com/

      Yeah, maintenance.

      Gerald
      http://BielerPress.blogspot.com



      --- In PPLetterpress@yahoogroups.com, Harold Kyle <harold@...> wrote:
      >
      > You're using all the right equipment and materials. The details on your
      > plate are likely detaching because they haven't received enough light during
      > the main exposure. The photopolymer material hasn't hardened all the way
      > down to the base. It separates during drying while it contracts--it has
      > nothing to hold on with.
      >
      > The bulbs most likely need replacing on your machine as you've surmised. In
      > the meantime you may have to keep increasing your main exposure to
      > compensate for their lack of output. Have you done a Stouffer test at the
      > edge of your bulbs recently? Fluorescent tubes put out less and less light
      > as they age. But you already knew this. Is this what you're asking?
      >
      > Harold
      >
      > On Mon, Aug 2, 2010 at 12:47 AM, idgradstudent <glenwoodemorris@...>wrote:
      >
      > >
      > >
      > > Harold,
      > >
      > > I'm using an older Jet A3 platemaker with analog controls (as opposed to
      > > the newer ones with digital controls).
      > >
      > > It uses a bank of lights.
      > >
      > > The separation is happening at some point between post-washout rinsing and
      > > the end of post-exposure. It is not 100% consistent but I will be examining
      > > more closely between drying and post-exposure in the future.
      > >
      > > I am using silver emulsion film, yes.
      > >
      > >
      > > Glenwood Morris
      > >
      > > Oslo Press Inc.
      > >
      > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com>,
      > > Harold Kyle <harold@> wrote:
      > > >
      > > > 5 minutes shouldn't be too long for the washout. You're fine there.
      > > >
      > > > What type of platemaker do you use? Point light source or a bank of
      > > lights?
      > > >
      > > > The photopolymer will separate for lots of reasons. It sounds like this
      > > is
      > > > happening during processing? During washout or during drying?
      > > >
      > > > Finally, are you using silver emulsion film? It sounds like you are. Just
      > > > checking.
      > > >
      > > > Would love to help but need more info.
      > > >
      > > > Harold
      > > >
      > > > On Sun, Aug 1, 2010 at 11:09 PM, idgradstudent <glenwoodemorris@
      > > ...>wrote:
      > >
      > > >
      > > > >
      > > > >
      > > > > More info:
      > > > >
      > > > > Fresh KF95 plates.
      > > > >
      > > > > I have a lot of "variables" like oldish brushes, and older bulbs that
      > > > > require a long exposure time (9 minutes according to my stouefer
      > > scale). So
      > > > > it would certainly be easy to dismiss my issues by saying "Hey, go do
      > > some
      > > > > basic maintenance to your platemaker" and you would be right. Aside
      > > from
      > > > > this relatively recent issue the plates have been good so I have opted
      > > to
      > > > > spend funds on other more pressing issues as a longer exposure time
      > > does not
      > > > > cost me much since I only make plates for myself and the cost for new
      > > bulbs
      > > > > and ballasts is not insignificant.
      > > > >
      > > > > My washout is probably too long (5 minutes), I will back it off and see
      > > if
      > > > > that works. When I first acquired the machine I established my exposure
      > > > > times with a scale and my washout times through trial and error but I
      > > may
      > > > > have just gone too far. Generally if I lose anything to this problem it
      > > is a
      > > > > crop mark on the edge of a plate, but recently I started losing thin
      > > script
      > > > > text and fine lines in graphics if they were also near the edge of the
      > > > > plate.
      > > > >
      > > > > My question included limited info as I wanted to know what the root
      > > cause
      > > > > of photopolymer/polyester separation was rather than have folks just
      > > tell me
      > > > > to do maintenance that is not really an option right now.
      > > > >
      > > > >
      > > > > Glenwood Morris
      > > > >
      > > > > Oslo Press Inc.
      > > > >
      > > > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com><PPLetterpress%
      > > 40yahoogroups.com>,
      > >
      > > > > "idgradstudent" <glenwoodemorris@> wrote:
      > > > > >
      > > > > > I did some searching and found several discussions about plates that
      > > have
      > > > > separated; i.e. the photopolymer has detached from the polyester
      > > backer.
      > > > > >
      > > > > > What I did not find in the discussion was any agreed upon conclusions
      > > > > about why exactly this happens (or I simply missed it).
      > > > > >
      > > > > > Does anyone know what causes this to occur? I am currently having
      > > > > problems with this with some of my plates and was wondering if there
      > > was a
      > > > > "known cause" before I just start changing things and hoping for the
      > > best.
      > > > > >
      > > > > > Thanks,
      > > > > >
      > > > > > Glenwood Morris
      > > > > >
      > > > > > Oslo Press Inc.
      > > > > >
      > > > >
      > > > >
      > > > >
      > > >
      > > >
      > > >
      > > > --
      > > > ---
      > > > Boxcar Press
      > > > 501 W. Fayette St. #222
      > > > Syracuse, NY 13204
      > > > www.boxcarpress.com
      > > >
      > >
      > >
      > >
      >
      >
      >
      > --
      > ---
      > Boxcar Press
      > 501 W. Fayette St. #222
      > Syracuse, NY 13204
      > www.boxcarpress.com
      >
    • Peter Fraterdeus
      Have you tried a 20-second back exposure before your vacuum main exposure? Particularly with hairline problems, and mysteriously moving commas, etc, it s
      Message 2 of 22 , Aug 2, 2010
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        Have you tried a 20-second back exposure before your vacuum main exposure?

        Particularly with hairline problems, and mysteriously moving commas, etc, it's pretty much 'de rigure' to prime the base a bit with a back exposure.

        At least in my experience ;-)

        Cheers

        PF

        ...
        Peter Fraterdeus
        Exquisite letterpress takes time™
        http://slowprint.com/

        IdeasWords : Idea Swords
        Communication Strategy
        Semiotx.com @ideaswords
      • Eric
        ... Too long in the bath. The material is absorbing moisture at the surface and expanding. It can t lengthen but instead assumes a wave form.
        Message 3 of 22 , Aug 2, 2010
        • 0 Attachment
          --- In PPLetterpress@yahoogroups.com, mike day <vangogh1888@...> wrote:
          > I have seen lines of type go squiggly
          > in an up and down line. Whether it is too long a washout and old plates, I
          > can't be sure.

          Too long in the bath. The material is absorbing moisture at the surface and expanding. It can't lengthen but instead assumes a wave form.
        • idgradstudent
          Thanks to Harold, Gerald, Peter, et al for the help and suggestions. I will have to do some testing at the edge of my exposure unit with my Stouffer scale and
          Message 4 of 22 , Aug 2, 2010
          • 0 Attachment
            Thanks to Harold, Gerald, Peter, et al for the help and suggestions.

            I will have to do some testing at the edge of my exposure unit with my Stouffer scale and see if I am getting different results there, which seems likely.

            I have had intermittent problems with overexposure in certain areas as well, which has kept me from just increasing my exposure time. I am guessing this is the "hot spots" that some bulbs can develop over time?

            Is there any detrimental effect to new bulbs if you replace just the bulbs rather than swapping the bulbs and the ballasts?

            I will try exposing the back of the plate for 20 seconds to see if it might be a temporary workaround.

            Glenwood Morris

            Oslo Press Inc.

            --- In PPLetterpress@yahoogroups.com, Harold Kyle <harold@...> wrote:
            >
            > You're using all the right equipment and materials. The details on your
            > plate are likely detaching because they haven't received enough light during
            > the main exposure. The photopolymer material hasn't hardened all the way
            > down to the base. It separates during drying while it contracts--it has
            > nothing to hold on with.
            >
            > The bulbs most likely need replacing on your machine as you've surmised. In
            > the meantime you may have to keep increasing your main exposure to
            > compensate for their lack of output. Have you done a Stouffer test at the
            > edge of your bulbs recently? Fluorescent tubes put out less and less light
            > as they age. But you already knew this. Is this what you're asking?
            >
            > Harold
            >
            > On Mon, Aug 2, 2010 at 12:47 AM, idgradstudent <glenwoodemorris@...>wrote:
            >
            > >
            > >
            > > Harold,
            > >
            > > I'm using an older Jet A3 platemaker with analog controls (as opposed to
            > > the newer ones with digital controls).
            > >
            > > It uses a bank of lights.
            > >
            > > The separation is happening at some point between post-washout rinsing and
            > > the end of post-exposure. It is not 100% consistent but I will be examining
            > > more closely between drying and post-exposure in the future.
            > >
            > > I am using silver emulsion film, yes.
            > >
            > >
            > > Glenwood Morris
            > >
            > > Oslo Press Inc.
            > >
            > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com>,
            > > Harold Kyle <harold@> wrote:
            > > >
            > > > 5 minutes shouldn't be too long for the washout. You're fine there.
            > > >
            > > > What type of platemaker do you use? Point light source or a bank of
            > > lights?
            > > >
            > > > The photopolymer will separate for lots of reasons. It sounds like this
            > > is
            > > > happening during processing? During washout or during drying?
            > > >
            > > > Finally, are you using silver emulsion film? It sounds like you are. Just
            > > > checking.
            > > >
            > > > Would love to help but need more info.
            > > >
            > > > Harold
            > > >
            > > > On Sun, Aug 1, 2010 at 11:09 PM, idgradstudent <glenwoodemorris@
            > > ...>wrote:
            > >
            > > >
            > > > >
            > > > >
            > > > > More info:
            > > > >
            > > > > Fresh KF95 plates.
            > > > >
            > > > > I have a lot of "variables" like oldish brushes, and older bulbs that
            > > > > require a long exposure time (9 minutes according to my stouefer
            > > scale). So
            > > > > it would certainly be easy to dismiss my issues by saying "Hey, go do
            > > some
            > > > > basic maintenance to your platemaker" and you would be right. Aside
            > > from
            > > > > this relatively recent issue the plates have been good so I have opted
            > > to
            > > > > spend funds on other more pressing issues as a longer exposure time
            > > does not
            > > > > cost me much since I only make plates for myself and the cost for new
            > > bulbs
            > > > > and ballasts is not insignificant.
            > > > >
            > > > > My washout is probably too long (5 minutes), I will back it off and see
            > > if
            > > > > that works. When I first acquired the machine I established my exposure
            > > > > times with a scale and my washout times through trial and error but I
            > > may
            > > > > have just gone too far. Generally if I lose anything to this problem it
            > > is a
            > > > > crop mark on the edge of a plate, but recently I started losing thin
            > > script
            > > > > text and fine lines in graphics if they were also near the edge of the
            > > > > plate.
            > > > >
            > > > > My question included limited info as I wanted to know what the root
            > > cause
            > > > > of photopolymer/polyester separation was rather than have folks just
            > > tell me
            > > > > to do maintenance that is not really an option right now.
            > > > >
            > > > >
            > > > > Glenwood Morris
            > > > >
            > > > > Oslo Press Inc.
            > > > >
            > > > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com><PPLetterpress%
            > > 40yahoogroups.com>,
            > >
            > > > > "idgradstudent" <glenwoodemorris@> wrote:
            > > > > >
            > > > > > I did some searching and found several discussions about plates that
            > > have
            > > > > separated; i.e. the photopolymer has detached from the polyester
            > > backer.
            > > > > >
            > > > > > What I did not find in the discussion was any agreed upon conclusions
            > > > > about why exactly this happens (or I simply missed it).
            > > > > >
            > > > > > Does anyone know what causes this to occur? I am currently having
            > > > > problems with this with some of my plates and was wondering if there
            > > was a
            > > > > "known cause" before I just start changing things and hoping for the
            > > best.
            > > > > >
            > > > > > Thanks,
            > > > > >
            > > > > > Glenwood Morris
            > > > > >
            > > > > > Oslo Press Inc.
            > > > > >
            > > > >
            > > > >
            > > > >
            > > >
            > > >
            > > >
            > > > --
            > > > ---
            > > > Boxcar Press
            > > > 501 W. Fayette St. #222
            > > > Syracuse, NY 13204
            > > > www.boxcarpress.com
            > > >
            > >
            > >
            > >
            >
            >
            >
            > --
            > ---
            > Boxcar Press
            > 501 W. Fayette St. #222
            > Syracuse, NY 13204
            > www.boxcarpress.com
            >
          • Harold Kyle
            Are any lights completely out? I think you only need to replace the bulbs, but make sure to replace all of them (based on what you ve described). Harold ... --
            Message 5 of 22 , Aug 2, 2010
            • 0 Attachment
              Are any lights completely out? I think you only need to replace the bulbs, but make sure to replace all of them (based on what you've described).

              Harold

              On Mon, Aug 2, 2010 at 4:00 PM, idgradstudent <glenwoodemorris@...> wrote:
               

              Thanks to Harold, Gerald, Peter, et al for the help and suggestions.

              I will have to do some testing at the edge of my exposure unit with my Stouffer scale and see if I am getting different results there, which seems likely.

              I have had intermittent problems with overexposure in certain areas as well, which has kept me from just increasing my exposure time. I am guessing this is the "hot spots" that some bulbs can develop over time?

              Is there any detrimental effect to new bulbs if you replace just the bulbs rather than swapping the bulbs and the ballasts?

              I will try exposing the back of the plate for 20 seconds to see if it might be a temporary workaround.

              Glenwood Morris

              Oslo Press Inc.

              --- In PPLetterpress@yahoogroups.com, Harold Kyle <harold@...> wrote:
              >
              > You're using all the right equipment and materials. The details on your
              > plate are likely detaching because they haven't received enough light during
              > the main exposure. The photopolymer material hasn't hardened all the way
              > down to the base. It separates during drying while it contracts--it has
              > nothing to hold on with.
              >
              > The bulbs most likely need replacing on your machine as you've surmised. In
              > the meantime you may have to keep increasing your main exposure to
              > compensate for their lack of output. Have you done a Stouffer test at the
              > edge of your bulbs recently? Fluorescent tubes put out less and less light
              > as they age. But you already knew this. Is this what you're asking?
              >
              > Harold
              >
              > On Mon, Aug 2, 2010 at 12:47 AM, idgradstudent <glenwoodemorris@...>wrote:
              >
              > >
              > >
              > > Harold,
              > >
              > > I'm using an older Jet A3 platemaker with analog controls (as opposed to
              > > the newer ones with digital controls).
              > >
              > > It uses a bank of lights.
              > >
              > > The separation is happening at some point between post-washout rinsing and
              > > the end of post-exposure. It is not 100% consistent but I will be examining
              > > more closely between drying and post-exposure in the future.
              > >
              > > I am using silver emulsion film, yes.
              > >
              > >
              > > Glenwood Morris
              > >
              > > Oslo Press Inc.
              > >
              > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com>,
              > > Harold Kyle <harold@> wrote:
              > > >
              > > > 5 minutes shouldn't be too long for the washout. You're fine there.
              > > >
              > > > What type of platemaker do you use? Point light source or a bank of
              > > lights?
              > > >
              > > > The photopolymer will separate for lots of reasons. It sounds like this
              > > is
              > > > happening during processing? During washout or during drying?
              > > >
              > > > Finally, are you using silver emulsion film? It sounds like you are. Just
              > > > checking.
              > > >
              > > > Would love to help but need more info.
              > > >
              > > > Harold
              > > >
              > > > On Sun, Aug 1, 2010 at 11:09 PM, idgradstudent <glenwoodemorris@
              > > ...>wrote:
              > >
              > > >
              > > > >
              > > > >
              > > > > More info:
              > > > >
              > > > > Fresh KF95 plates.
              > > > >
              > > > > I have a lot of "variables" like oldish brushes, and older bulbs that
              > > > > require a long exposure time (9 minutes according to my stouefer
              > > scale). So
              > > > > it would certainly be easy to dismiss my issues by saying "Hey, go do
              > > some
              > > > > basic maintenance to your platemaker" and you would be right. Aside
              > > from
              > > > > this relatively recent issue the plates have been good so I have opted
              > > to
              > > > > spend funds on other more pressing issues as a longer exposure time
              > > does not
              > > > > cost me much since I only make plates for myself and the cost for new
              > > bulbs
              > > > > and ballasts is not insignificant.
              > > > >
              > > > > My washout is probably too long (5 minutes), I will back it off and see
              > > if
              > > > > that works. When I first acquired the machine I established my exposure
              > > > > times with a scale and my washout times through trial and error but I
              > > may
              > > > > have just gone too far. Generally if I lose anything to this problem it
              > > is a
              > > > > crop mark on the edge of a plate, but recently I started losing thin
              > > script
              > > > > text and fine lines in graphics if they were also near the edge of the
              > > > > plate.
              > > > >
              > > > > My question included limited info as I wanted to know what the root
              > > cause
              > > > > of photopolymer/polyester separation was rather than have folks just
              > > tell me
              > > > > to do maintenance that is not really an option right now.
              > > > >
              > > > >
              > > > > Glenwood Morris
              > > > >
              > > > > Oslo Press Inc.
              > > > >
              > > > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com><PPLetterpress%
              > > 40yahoogroups.com>,
              > >
              > > > > "idgradstudent" <glenwoodemorris@> wrote:
              > > > > >
              > > > > > I did some searching and found several discussions about plates that
              > > have
              > > > > separated; i.e. the photopolymer has detached from the polyester
              > > backer.
              > > > > >
              > > > > > What I did not find in the discussion was any agreed upon conclusions
              > > > > about why exactly this happens (or I simply missed it).
              > > > > >
              > > > > > Does anyone know what causes this to occur? I am currently having
              > > > > problems with this with some of my plates and was wondering if there
              > > was a
              > > > > "known cause" before I just start changing things and hoping for the
              > > best.
              > > > > >
              > > > > > Thanks,
              > > > > >
              > > > > > Glenwood Morris
              > > > > >
              > > > > > Oslo Press Inc.
              > > > > >
              > > > >
              > > > >
              > > > >
              > > >
              > > >
              > > >
              > > > --
              > > > ---
              > > > Boxcar Press
              > > > 501 W. Fayette St. #222
              > > > Syracuse, NY 13204
              > > > www.boxcarpress.com
              > > >
              > >
              > >
              > >
              >
              >
              >
              > --
              > ---
              > Boxcar Press
              > 501 W. Fayette St. #222
              > Syracuse, NY 13204
              > www.boxcarpress.com
              >




              --
              ---
              Boxcar Press
              501 W. Fayette St. #222
              Syracuse, NY  13204
              www.boxcarpress.com
            • bielerpr
              Glenwood This article might help http://bielerpressxi.blogspot.com/2006/03/on-scales-and-lamps.html You would not want to swap out a ballast unless one is
              Message 6 of 22 , Aug 2, 2010
              • 0 Attachment
                Glenwood

                This article might help

                http://bielerpressxi.blogspot.com/2006/03/on-scales-and-lamps.html

                You would not want to swap out a ballast unless one is malfunctioning. They last far longer than bulbs. If your bulbs all turn on, your ballasts are working. If a bulb or bulbs are acting erratically you likely would have a wiring/connection problem.

                That suggestion re: back exposure is likely in reference to the KF152 plates not the KF95. The KF152 is a bit softer and thicker plate and that little trick is used to strengthen the relief structure. I doubt the KF95 would benefit from this as it does not share the problems that have been related regarding the KF152. Note that sheet photopolymer plates are already back-exposed by the manufacturer.

                Gerald
                http://BielerPress.blogspsot.com



                --- In PPLetterpress@yahoogroups.com, "idgradstudent" <glenwoodemorris@...> wrote:
                >
                > Thanks to Harold, Gerald, Peter, et al for the help and suggestions.
                >
                > I will have to do some testing at the edge of my exposure unit with my Stouffer scale and see if I am getting different results there, which seems likely.
                >
                > I have had intermittent problems with overexposure in certain areas as well, which has kept me from just increasing my exposure time. I am guessing this is the "hot spots" that some bulbs can develop over time?
                >
                > Is there any detrimental effect to new bulbs if you replace just the bulbs rather than swapping the bulbs and the ballasts?
                >
                > I will try exposing the back of the plate for 20 seconds to see if it might be a temporary workaround.
                >
                > Glenwood Morris
                >
                > Oslo Press Inc.
                >
                > --- In PPLetterpress@yahoogroups.com, Harold Kyle <harold@> wrote:
                > >
                > > You're using all the right equipment and materials. The details on your
                > > plate are likely detaching because they haven't received enough light during
                > > the main exposure. The photopolymer material hasn't hardened all the way
                > > down to the base. It separates during drying while it contracts--it has
                > > nothing to hold on with.
                > >
                > > The bulbs most likely need replacing on your machine as you've surmised. In
                > > the meantime you may have to keep increasing your main exposure to
                > > compensate for their lack of output. Have you done a Stouffer test at the
                > > edge of your bulbs recently? Fluorescent tubes put out less and less light
                > > as they age. But you already knew this. Is this what you're asking?
                > >
                > > Harold
                > >
                > > On Mon, Aug 2, 2010 at 12:47 AM, idgradstudent <glenwoodemorris@>wrote:
                > >
                > > >
                > > >
                > > > Harold,
                > > >
                > > > I'm using an older Jet A3 platemaker with analog controls (as opposed to
                > > > the newer ones with digital controls).
                > > >
                > > > It uses a bank of lights.
                > > >
                > > > The separation is happening at some point between post-washout rinsing and
                > > > the end of post-exposure. It is not 100% consistent but I will be examining
                > > > more closely between drying and post-exposure in the future.
                > > >
                > > > I am using silver emulsion film, yes.
                > > >
                > > >
                > > > Glenwood Morris
                > > >
                > > > Oslo Press Inc.
                > > >
                > > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com>,
                > > > Harold Kyle <harold@> wrote:
                > > > >
                > > > > 5 minutes shouldn't be too long for the washout. You're fine there.
                > > > >
                > > > > What type of platemaker do you use? Point light source or a bank of
                > > > lights?
                > > > >
                > > > > The photopolymer will separate for lots of reasons. It sounds like this
                > > > is
                > > > > happening during processing? During washout or during drying?
                > > > >
                > > > > Finally, are you using silver emulsion film? It sounds like you are. Just
                > > > > checking.
                > > > >
                > > > > Would love to help but need more info.
                > > > >
                > > > > Harold
                > > > >
                > > > > On Sun, Aug 1, 2010 at 11:09 PM, idgradstudent <glenwoodemorris@
                > > > ...>wrote:
                > > >
                > > > >
                > > > > >
                > > > > >
                > > > > > More info:
                > > > > >
                > > > > > Fresh KF95 plates.
                > > > > >
                > > > > > I have a lot of "variables" like oldish brushes, and older bulbs that
                > > > > > require a long exposure time (9 minutes according to my stouefer
                > > > scale). So
                > > > > > it would certainly be easy to dismiss my issues by saying "Hey, go do
                > > > some
                > > > > > basic maintenance to your platemaker" and you would be right. Aside
                > > > from
                > > > > > this relatively recent issue the plates have been good so I have opted
                > > > to
                > > > > > spend funds on other more pressing issues as a longer exposure time
                > > > does not
                > > > > > cost me much since I only make plates for myself and the cost for new
                > > > bulbs
                > > > > > and ballasts is not insignificant.
                > > > > >
                > > > > > My washout is probably too long (5 minutes), I will back it off and see
                > > > if
                > > > > > that works. When I first acquired the machine I established my exposure
                > > > > > times with a scale and my washout times through trial and error but I
                > > > may
                > > > > > have just gone too far. Generally if I lose anything to this problem it
                > > > is a
                > > > > > crop mark on the edge of a plate, but recently I started losing thin
                > > > script
                > > > > > text and fine lines in graphics if they were also near the edge of the
                > > > > > plate.
                > > > > >
                > > > > > My question included limited info as I wanted to know what the root
                > > > cause
                > > > > > of photopolymer/polyester separation was rather than have folks just
                > > > tell me
                > > > > > to do maintenance that is not really an option right now.
                > > > > >
                > > > > >
                > > > > > Glenwood Morris
                > > > > >
                > > > > > Oslo Press Inc.
                > > > > >
                > > > > > --- In PPLetterpress@yahoogroups.com <PPLetterpress%40yahoogroups.com><PPLetterpress%
                > > > 40yahoogroups.com>,
                > > >
                > > > > > "idgradstudent" <glenwoodemorris@> wrote:
                > > > > > >
                > > > > > > I did some searching and found several discussions about plates that
                > > > have
                > > > > > separated; i.e. the photopolymer has detached from the polyester
                > > > backer.
                > > > > > >
                > > > > > > What I did not find in the discussion was any agreed upon conclusions
                > > > > > about why exactly this happens (or I simply missed it).
                > > > > > >
                > > > > > > Does anyone know what causes this to occur? I am currently having
                > > > > > problems with this with some of my plates and was wondering if there
                > > > was a
                > > > > > "known cause" before I just start changing things and hoping for the
                > > > best.
                > > > > > >
                > > > > > > Thanks,
                > > > > > >
                > > > > > > Glenwood Morris
                > > > > > >
                > > > > > > Oslo Press Inc.
                > > > > > >
                > > > > >
                > > > > >
                > > > > >
                > > > >
                > > > >
                > > > >
                > > > > --
                > > > > ---
                > > > > Boxcar Press
                > > > > 501 W. Fayette St. #222
                > > > > Syracuse, NY 13204
                > > > > www.boxcarpress.com
                > > > >
                > > >
                > > >
                > > >
                > >
                > >
                > >
                > > --
                > > ---
                > > Boxcar Press
                > > 501 W. Fayette St. #222
                > > Syracuse, NY 13204
                > > www.boxcarpress.com
                > >
                >
              • Eric
                ... If your hot spots float around to different places, another possibility is bad contact between neg and plate. That causes a general overexposure, where
                Message 7 of 22 , Aug 2, 2010
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                  --- In PPLetterpress@yahoogroups.com, "idgradstudent" <glenwoodemorris@...> wrote:
                  >
                  > I have had intermittent problems with overexposure in certain areas as well, which has
                  > kept me from just increasing my exposure time. I am guessing this is the "hot spots"
                  > that some bulbs can develop over time?

                  If your hot spots float around to different places, another possibility is bad contact between neg and plate. That causes a general overexposure, where light leaks around the edges of the film image and exposes the non-image area.
                • painted_tongue
                  This calls to mind something we were experiencing last year. We were using HX145 at the time, if I recall correctly. We were having some issues with certain
                  Message 8 of 22 , Aug 3, 2010
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                    This calls to mind something we were experiencing last year. We were using HX145 at the time, if I recall correctly. We were having some issues with certain plates coming out brittle, cracking, and separating from the backing. Other plates worked, but you could tell from a slight color variation that they were fragile. Still other plates worked fine. After some trial and observation, one of my cohorts felt it was the length of post exposure. I was under the impression (based on something I was taught about a different plate material) that you couldn't over post expose. However as we worked through the problem, I had to agree, that it was the length of time in post exposure.

                    To drive the point home, one weekend a plate was accidently left sitting out in a place where the afternoon sunlight would reach it. The plate had already been made and post exposed. When we returned, the whole thing had thousands of fissures.

                    I wonder if as you're compensating for the bulbs aging by increasing exposure, post exposure, or both, you're winding up with too much time in the direct uv light?

                    Good luck!
                    Kim Vanderheiden

                    Painted Tongue Press


                    --- In PPLetterpress@yahoogroups.com, "idgradstudent" <glenwoodemorris@...> wrote:
                    >
                    > Thanks to Harold, Gerald, Peter, et al for the help and suggestions.
                    >
                    > I will have to do some testing at the edge of my exposure unit with my Stouffer scale and see if I am getting different results there, which seems likely.
                    >
                    > I have had intermittent problems with overexposure in certain areas as well, which has kept me from just increasing my exposure time. I am guessing this is the "hot spots" that some bulbs can develop over time?
                    >
                    > Is there any detrimental effect to new bulbs if you replace just the bulbs rather than swapping the bulbs and the ballasts?
                    >
                    > I will try exposing the back of the plate for 20 seconds to see if it might be a temporary workaround.
                    >
                    > Glenwood Morris
                    >
                    > Oslo Press Inc.
                  • Eric
                    ... In one batch of HX145, I saw that happen to a plate that was left out under flourescent room light. The same batch could lose periods if you planed it too
                    Message 9 of 22 , Aug 3, 2010
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                      --- In PPLetterpress@yahoogroups.com, "painted_tongue" <paintedtongue@...> wrote:
                      >
                      > To drive the point home, one weekend a plate was accidently left sitting out in a place where the afternoon sunlight would reach it. The plate had already been made and post exposed. When we returned, the whole thing had thousands of fissures.
                      >
                      In one batch of HX145, I saw that happen to a plate that was left out under flourescent room light. The same batch could lose periods if you planed it too hard or let it slap the Bunting. This was about 15 years ago, haven't seen that fragility in HX145 since.
                      --Eric Holub, SF
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