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Re: [PPLetterpress] Processing plates by hand

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  • Katie Harper
    Hi You ll probably get a lot of responses (this subject comes up a lot). I think there might be some information about exposing and hand washing of polymer
    Message 1 of 12 , Dec 3, 2002
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      Hi

      You'll probably get a lot of responses (this subject comes up a lot). I
      think there might be some information about exposing and hand washing of
      polymer plates on the Yahoo groups web site, but am not sure.

      There are many on this list who know a lot more about this than I do. But to
      make a long story short, it's really not difficult at all to do your own
      plates. In fact, it's done quite often in schools because polymer is taking
      over more toxic processes such as etching zinc or copper with nitric acid.
      What IS difficult, at least in my experience, is getting good detail, which
      requires at minimum: 1. excellent negatives (with good dense blacks and
      clear whites), exposed so that the emulsion of the film touches the emulsion
      of the plate; 2. good vacuum seal during exposure; 3. proper washout temp.,
      proper washout time, proper washout motion (not too hard, not too soft). I
      have wasted many a plate in my day, and now my rule of thumb is: if the type
      is below 14 point or has serifs, I have the plate made professionally.

      Having said that, I still use crude but effective methods to do my own
      plates for experimental work, or when detail in the artwork is not critical.
      I have even done them with negatives that I have made in my 600 dpi laser
      printer, by printing onto transparency film. I expose to sunlight (1-2 mins
      if it's bright and sunny; 5-7 mins if cloudy) and lay the negative on the
      plate, emulsion to emulsion, wrong reading, under glass, with weights around
      the outside of the glass to hold it down. After exposure, I wash in a photo
      tray filled with water at about 80 degrees (I have heard many different
      temperatures mentioned, but that is what works for me), gently brushing
      around the plate with my Boxcar Brush (special soft brush) for about 5
      mins., changing water frequently to keep it clean and up to temp. After
      washing, I run cool water over the plate, very gently to keep from getting
      bubbles. Then I post expose, ie, put the plate back into the sunlight with
      no glass for another 5 mins. or so. If I need to use the plate right away, I
      dry it with a hair dryer. I once used this method in an emergency, when I
      was on press and smashed a metal plate, destroying one number. I made a
      polymer plate and glued it down on the wood base and it printed quite well.
      An expert would have noticed the difference, but my client didn't see a
      thing, and the job was saved.

      A lot of this is variable; the more control you want in the image, the more
      you will have to carefully control all the variables. Some of this is
      outlined in a book called "Printmaking in the Sun" or something like that.

      Good luck!


      Katie Harper
      Ars Brevis Press
      Cincinnati, OH
      513-233-9588
      http://www.arsbrevispress.com





      > From: "riverrider2" <riverrider2@...>
      > Reply-To: PPLetterpress@yahoogroups.com
      > Date: Tue, 03 Dec 2002 19:44:49 -0000
      > To: PPLetterpress@yahoogroups.com
      > Subject: [PPLetterpress] Processing plates by hand
      >
      > Although I have yet to attempt printing with polymer plates, I'm on
      > the verge of buying a base and giving it a go. I've looked into a
      > local plate processor and I think that the charge they quoted me for
      > processing a plate is too much for what I'd do with it. I think that
      > doing on my own would make this a feasible option for me, but I'm not
      > sure how "touchy" these plates are to make.
      >
      > Can any of you veteran PP printers give me an idea as to how
      > difficult it is to expose and process a plate by hand? I know the
      > basics of the process, but have never actually done it. Thanks
      >
      >
      > • To respond to a post or post a message to the membership:
      > PPLetterpress@yahoogroups.com
      > • Encountering problems? contact:
      > PPLetterpress-owner@yahoogroups.com
      > • To unsubscribe:
      > PPLetterpress-unsubscribe@yahoogroups.com
      >
      > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
      >
      >
    • Ed Inman
      The sun is great for re-exposure when available, but unreliable for general exposure. What if you need a plate when it s cloudy, raining or late at night???
      Message 2 of 12 , Dec 3, 2002
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        The sun is great for re-exposure when available, but unreliable for general
        exposure. What if you need a plate when it's cloudy, raining or late at
        night???

        IMO, the world's cheapest reliable polymer platemaking system consists of a
        used "Sun Gun" (they were sold by Sylvania & Kodak as movie lights and trade
        daily for about $5-$10 on ebay), a weighted plate glass, a horse-hair brush,
        and a kitchen sink.

        Expose normal line artwork negative under Sun Gun from about 3 feet for 30
        minutes under the glass (45 minutes for super fine artwork or halftones).
        Divide line artwork exposure time from slightly different angles (about 10 min
        from lower left, 10 min from right, 10 min. from top).

        Wash plate under running warm water while gently and slowly brushing the
        plate. Do not get too impatient and try to brush the plate too hard or
        vigorously--this may break off delicate pieces.

        You should have a perfect plate ready for drying and re-exposure after about 7
        minutes of brushing.

        It is slow and tedious, but I have done dozens of critical line artwork plates
        this way and even once a 100-line halftone with virtually, perfect, consistent
        results.

        Ed
      • Katie Harper
        Ed: Your Sun Gun method sounds intriguing. Are you making your own negatives? Katie Harper Ars Brevis Press Cincinnati, OH 513-233-9588
        Message 3 of 12 , Dec 3, 2002
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          Ed: Your Sun Gun method sounds intriguing. Are you making your own
          negatives?


          Katie Harper
          Ars Brevis Press
          Cincinnati, OH
          513-233-9588
          http://www.arsbrevispress.com





          > From: " Ed Inman"<edinman@...>
          > Reply-To: PPLetterpress@yahoogroups.com
          > Date: Tue, 03 Dec 2002 13:00:03 -0800
          > To: PPLetterpress@yahoogroups.com
          > Subject: Re: [PPLetterpress] Processing plates by hand
          >
          > The sun is great for re-exposure when available, but unreliable for general
          > exposure. What if you need a plate when it's cloudy, raining or late at
          > night???
          >
          > IMO, the world's cheapest reliable polymer platemaking system consists of a
          > used "Sun Gun" (they were sold by Sylvania & Kodak as movie lights and trade
          > daily for about $5-$10 on ebay), a weighted plate glass, a horse-hair brush,
          > and a kitchen sink.
          >
          > Expose normal line artwork negative under Sun Gun from about 3 feet for 30
          > minutes under the glass (45 minutes for super fine artwork or halftones).
          > Divide line artwork exposure time from slightly different angles (about 10 min
          > from lower left, 10 min from right, 10 min. from top).
          >
          > Wash plate under running warm water while gently and slowly brushing the
          > plate. Do not get too impatient and try to brush the plate too hard or
          > vigorously--this may break off delicate pieces.
          >
          > You should have a perfect plate ready for drying and re-exposure after about 7
          > minutes of brushing.
          >
          > It is slow and tedious, but I have done dozens of critical line artwork plates
          > this way and even once a 100-line halftone with virtually, perfect, consistent
          > results.
          >
          > Ed
          >
          >
          > • To respond to a post or post a message to the membership:
          > PPLetterpress@yahoogroups.com
          > • Encountering problems? contact:
          > PPLetterpress-owner@yahoogroups.com
          > • To unsubscribe:
          > PPLetterpress-unsubscribe@yahoogroups.com
          >
          > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
          >
          >
        • Joel Benson
          It is my experience that there is a lot of flexibility in the various plate materials, regarding exposure time and washout temperature, etc. I suppose that is
          Message 4 of 12 , Dec 3, 2002
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            It is my experience that there is a lot of flexibility in the various plate materials, regarding exposure time and washout temperature, etc. I suppose that is why making them by hand is possible at all. The great advantage of the commercial platemaking machines is the consistency, and the ability to make plates at the limits of what the material is designed to do- notably, very fine detail.

            I use a homemade exposure unit, and I highly recommend getting a Stouffer scale for measuring the amount of UV exposure that your plate is getting. It only cost $5 or $6, and has saved me so much guesswork and trial-and-error, especially as I experimented with different plate materials. The specs for the plate material you are using will specify a certain level on the Stouffer scale for proper exposure, and all you have to do is do trial exposures on little scraps of material until you get it.

            For instance, the plate material I am using now called for a 5 minute exposure and a solid step 20 on the Stouffer scale, but I found that my exposure unit needed 8 or 10 minutes to hit the Step 20. And when I increased my exposure time, lo! suddenly the periods were holding up and all the serif were there! Hooray!

            Good luck!

            Joel Benson
            Dependable Letterpress
            San Francisco




            -----Original Message-----
            From: Katie Harper [mailto:knharper@...]
            Sent: Tuesday, December 03, 2002 12:12 PM
            To: PPLetterpress@yahoogroups.com
            Subject: Re: [PPLetterpress] Processing plates by hand


            Hi

            You'll probably get a lot of responses (this subject comes up a lot). I
            think there might be some information about exposing and hand washing of
            polymer plates on the Yahoo groups web site, but am not sure.

            There are many on this list who know a lot more about this than I do. But to
            make a long story short, it's really not difficult at all to do your own
            plates. In fact, it's done quite often in schools because polymer is taking
            over more toxic processes such as etching zinc or copper with nitric acid.
            What IS difficult, at least in my experience, is getting good detail, which
            requires at minimum: 1. excellent negatives (with good dense blacks and
            clear whites), exposed so that the emulsion of the film touches the emulsion
            of the plate; 2. good vacuum seal during exposure; 3. proper washout temp.,
            proper washout time, proper washout motion (not too hard, not too soft). I
            have wasted many a plate in my day, and now my rule of thumb is: if the type
            is below 14 point or has serifs, I have the plate made professionally.

            Having said that, I still use crude but effective methods to do my own
            plates for experimental work, or when detail in the artwork is not critical.
            I have even done them with negatives that I have made in my 600 dpi laser
            printer, by printing onto transparency film. I expose to sunlight (1-2 mins
            if it's bright and sunny; 5-7 mins if cloudy) and lay the negative on the
            plate, emulsion to emulsion, wrong reading, under glass, with weights around
            the outside of the glass to hold it down. After exposure, I wash in a photo
            tray filled with water at about 80 degrees (I have heard many different
            temperatures mentioned, but that is what works for me), gently brushing
            around the plate with my Boxcar Brush (special soft brush) for about 5
            mins., changing water frequently to keep it clean and up to temp. After
            washing, I run cool water over the plate, very gently to keep from getting
            bubbles. Then I post expose, ie, put the plate back into the sunlight with
            no glass for another 5 mins. or so. If I need to use the plate right away, I
            dry it with a hair dryer. I once used this method in an emergency, when I
            was on press and smashed a metal plate, destroying one number. I made a
            polymer plate and glued it down on the wood base and it printed quite well.
            An expert would have noticed the difference, but my client didn't see a
            thing, and the job was saved.

            A lot of this is variable; the more control you want in the image, the more
            you will have to carefully control all the variables. Some of this is
            outlined in a book called "Printmaking in the Sun" or something like that.

            Good luck!


            Katie Harper
            Ars Brevis Press
            Cincinnati, OH
            513-233-9588
            http://www.arsbrevispress.com





            > From: "riverrider2" <riverrider2@...>
            > Reply-To: PPLetterpress@yahoogroups.com
            > Date: Tue, 03 Dec 2002 19:44:49 -0000
            > To: PPLetterpress@yahoogroups.com
            > Subject: [PPLetterpress] Processing plates by hand
            >
            > Although I have yet to attempt printing with polymer plates, I'm on
            > the verge of buying a base and giving it a go. I've looked into a
            > local plate processor and I think that the charge they quoted me for
            > processing a plate is too much for what I'd do with it. I think that
            > doing on my own would make this a feasible option for me, but I'm not
            > sure how "touchy" these plates are to make.
            >
            > Can any of you veteran PP printers give me an idea as to how
            > difficult it is to expose and process a plate by hand? I know the
            > basics of the process, but have never actually done it. Thanks
            >
            >
            > * To respond to a post or post a message to the membership:
            > PPLetterpress@yahoogroups.com
            > * Encountering problems? contact:
            > PPLetterpress-owner@yahoogroups.com
            > * To unsubscribe:
            > PPLetterpress-unsubscribe@yahoogroups.com
            >
            > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
            >
            >


            * To respond to a post or post a message to the membership:
            PPLetterpress@yahoogroups.com
            * Encountering problems? contact:
            PPLetterpress-owner@yahoogroups.com
            * To unsubscribe:
            PPLetterpress-unsubscribe@yahoogroups.com

            Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
          • Gerald Lange
            ... Hello I can t answer the last part of this as I ve never made a plate by hand. I have placed whatever alt processing info I have been able to find at
            Message 5 of 12 , Dec 4, 2002
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              --- In PPLetterpress@y..., "riverrider2" <riverrider2@y...> wrote:
              > Although I have yet to attempt printing with polymer plates, I'm on
              > the verge of buying a base and giving it a go. I've looked into a
              > local plate processor and I think that the charge they quoted me for
              > processing a plate is too much for what I'd do with it. I think that
              > doing on my own would make this a feasible option for me, but I'm not
              > sure how "touchy" these plates are to make.
              >
              > Can any of you veteran PP printers give me an idea as to how
              > difficult it is to expose and process a plate by hand? I know the
              > basics of the process, but have never actually done it. Thanks

              Hello

              I can't answer the last part of this as I've never made a plate by
              hand. I have placed whatever alt processing info I have been able to
              find at various places on site. Katie's info here is probably as
              detailed as you are going to get. But alt processing is very subjective.

              I can deal somewhat with your concerns about plate processing charges.
              I won't involve you with the cost of the machine, water, electrical,
              labor, etc that the processors will throw up their arms about, just
              the cost of plates. Though those other factors are certainly a
              consideration in the standardization of pricing, such as it is.

              Processors will buy raw plates in bulk so they get better discounts.
              They have to. They have to maintain inventory. The occasional plate
              purchaser pays more at the retail end since you are not buying in
              quantity. That aside, you are paying approximately two and a half to
              three times the cost of the plate to the processor depending upon
              their pricing. That's at the price they pay at discount, not the price
              you would have to pay to buy raw plates in small quantities. In both
              cases, there is also waste dependent upon cutting.

              I'd suspect that if you blow one plate out of two (maybe two and a
              half, maybe three) you are costing yourself more money than if you'd
              gone with the processor. But even the plates that you do not blow will
              not be at the level of quality that a processor can provide. Note:
              processors blow plate as well, you just won't hear about it.

              In terms of picking a processor, go with pricing or reputation and
              reliability, whatever suits you. Beyond that, if someone puts in their
              promotional literature that they make the "best" plates (and there are
              a few of them out there), that's BS. Some may be more concerned than
              others but it's all just a matter of pushing buttons and timing.

              Gerald
            • Tim Honnor
              Hullo from Scotland. We tried and tried to make plates by hand - but only with some success. The wash-out is really problematical and we could never hold fine
              Message 6 of 12 , Dec 4, 2002
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                Hullo from Scotland.
                We tried and tried to make plates by hand - but only with some success.
                The wash-out is really problematical and we could never hold fine lines
                and it was all a bit hit and miss. Since getting an auto wash-up unit we
                have made beautiful plates and are able to hold VERY fine detail.
                Tim Honnor of Piccolo Press - Nairn - Scotland

                In message <askhhk+eth8@...>, Gerald Lange
                <bieler@...> writes
                >--- In PPLetterpress@y..., "riverrider2" <riverrider2@y...> wrote:
                >> Although I have yet to attempt printing with polymer plates, I'm on
                >> the verge of buying a base and giving it a go. I've looked into a
                >> local plate processor and I think that the charge they quoted me for
                >> processing a plate is too much for what I'd do with it. I think that
                >> doing on my own would make this a feasible option for me, but I'm not
                >> sure how "touchy" these plates are to make.
                >>
                >> Can any of you veteran PP printers give me an idea as to how
                >> difficult it is to expose and process a plate by hand? I know the
                >> basics of the process, but have never actually done it. Thanks
                >
                >Hello
                >
                >I can't answer the last part of this as I've never made a plate by
                >hand. I have placed whatever alt processing info I have been able to
                >find at various places on site. Katie's info here is probably as
                >detailed as you are going to get. But alt processing is very subjective.
                >
                >I can deal somewhat with your concerns about plate processing charges.
                >I won't involve you with the cost of the machine, water, electrical,
                >labor, etc that the processors will throw up their arms about, just
                >the cost of plates. Though those other factors are certainly a
                >consideration in the standardization of pricing, such as it is.
                >
                >Processors will buy raw plates in bulk so they get better discounts.
                >They have to. They have to maintain inventory. The occasional plate
                >purchaser pays more at the retail end since you are not buying in
                >quantity. That aside, you are paying approximately two and a half to
                >three times the cost of the plate to the processor depending upon
                >their pricing. That's at the price they pay at discount, not the price
                >you would have to pay to buy raw plates in small quantities. In both
                >cases, there is also waste dependent upon cutting.
                >
                >I'd suspect that if you blow one plate out of two (maybe two and a
                >half, maybe three) you are costing yourself more money than if you'd
                >gone with the processor. But even the plates that you do not blow will
                >not be at the level of quality that a processor can provide. Note:
                >processors blow plate as well, you just won't hear about it.
                >
                >In terms of picking a processor, go with pricing or reputation and
                >reliability, whatever suits you. Beyond that, if someone puts in their
                >promotional literature that they make the "best" plates (and there are
                >a few of them out there), that's BS. Some may be more concerned than
                >others but it's all just a matter of pushing buttons and timing.
                >
                >Gerald
                >
                >
                >
                >
                >
                >• To respond to a post or post a message to the membership:
                >PPLetterpress@yahoogroups.com
                >• Encountering problems? contact:
                >PPLetterpress-owner@yahoogroups.com
                >• To unsubscribe:
                >PPLetterpress-unsubscribe@yahoogroups.com
                >
                >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                >
                >

                --


                Tim Honnor - Piccolo Press - 90 Harbour Street - Nairn - IV12 4PG
                tel: 01667 454508 fax 01667 454509
                www.piccolopress.co.uk
              • mossgate
                I have only had a few months experience with photopolymer plates but have found the experience fun, simple & successful. I come from the intaglio perspective
                Message 7 of 12 , Dec 4, 2002
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                  I have only had a few months experience with photopolymer plates but
                  have found the experience fun, simple & successful. I come from the
                  intaglio perspective so this might be subject to further comment by
                  letterpress folks. I recently purchased a somewhat neglected
                  Vandercook SP-15 but haven't yet had the time to get it up and
                  running
                  to see how my present technique translates to letterpress.

                  For one thing, I am using the type of photopolymer plates that are
                  exposed to the sun..."sun plates." I was taught to do my exposing on
                  sunny days only, which up to this point I have done. Not a practical
                  method for commercial purposes.

                  I place my photopolymer plate on a piece of masonite that I backed
                  with felt. I place the plate emulsion side up onto the felted
                  masonite
                  and place my transparency emulsion side down onto the emulsion of the
                  pp plate. I place a piece of 1/4 inch glass over the transparency
                  and
                  clamp the whole thing on four sides.

                  I throw a towel over the glass and pull it off once I'm outside and
                  ready to expose. Use a watch with a second hand or stopwatch.(Make
                  sure no lint, hair, or whatever is sitting on the glass....) I
                  expose
                  for between 1 minute and 20 seconds to 1 and a half seconds.

                  I rince the pp plate under the kitchen faucet using cool to luke warm
                  water for only one minute gently scrubbing with a soft bristle brush.
                  I then blot the plate with newspaper which leaves no lint and removes
                  potential watermarks beautifully.

                  I then leave my plate in the sun for several hours before letting dry
                  inside for another 24 hours.

                  I get very fine detail from my photo images.

                  I find that making a transparency that has moderately "thin" blacks
                  helps keep the pp plate from washing out(etching)too deeply thus
                  holding too much ink when one goes to make an intaglio print. Maybe
                  this is not a problem with relief printing.

                  Best thing to do is print test strips to understand how exposure time
                  and the intensity of the transparency's blacks effect plate detail
                  and the printing outcome.

                  I have been purchasing my steel backed sun plates from Daniel Smith.
                  I'd love to find pp plates elsewhere at a competative price.

                  Aurora Oberloh
                  Phoenix, AZ
                • Gerald Lange
                  ... Hmmm, interesting. This is a problem with relief but in a different way. Would a longer exposure in the sun compensate for thin blacks in regard to the
                  Message 8 of 12 , Dec 5, 2002
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                    >
                    > I get very fine detail from my photo images.
                    >
                    > I find that making a transparency that has moderately "thin" blacks
                    > helps keep the pp plate from washing out(etching)too deeply thus
                    > holding too much ink when one goes to make an intaglio print. Maybe
                    > this is not a problem with relief printing.
                    >

                    > Aurora Oberloh
                    > Phoenix, AZ

                    Hmmm, interesting. This is a problem with relief but in a different
                    way. Would a longer exposure in the sun compensate for "thin" blacks
                    in regard to the deep etch? Normally the longer the initial exposure
                    the shallower the relief will become as the structure begins to fill
                    in. Are you suggesting less contrast when you say "thin" blacks? Photo
                    images tend to be problematic with relief. Difficult to capture the
                    detail in the processing since it requires longer exposure while also
                    then having to deal with the problem of the shallower underlying
                    structure during printing. Would a shorter exposure with less contrast
                    in the grays possibly resolve this?

                    Gerald

                    Gerald
                  • mossgate
                    ... blacks ... Maybe ... Photo ... also ... contrast ... First, let me make a correction. I said I exposed my plates for one minute and twenty seconds to one
                    Message 9 of 12 , Dec 5, 2002
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                      --- In PPLetterpress@y..., "Gerald Lange" <bieler@w...> wrote:
                      >
                      > >
                      > > I get very fine detail from my photo images.
                      > >
                      > > I find that making a transparency that has moderately "thin"
                      blacks
                      > > helps keep the pp plate from washing out(etching)too deeply thus
                      > > holding too much ink when one goes to make an intaglio print.
                      Maybe
                      > > this is not a problem with relief printing.
                      > >
                      >
                      > > Aurora Oberloh
                      > > Phoenix, AZ
                      >
                      > Hmmm, interesting. This is a problem with relief but in a different
                      > way. Would a longer exposure in the sun compensate for "thin" blacks
                      > in regard to the deep etch? Normally the longer the initial exposure
                      > the shallower the relief will become as the structure begins to fill
                      > in. Are you suggesting less contrast when you say "thin" blacks?
                      Photo
                      > images tend to be problematic with relief. Difficult to capture the
                      > detail in the processing since it requires longer exposure while
                      also
                      > then having to deal with the problem of the shallower underlying
                      > structure during printing. Would a shorter exposure with less
                      contrast
                      > in the grays possibly resolve this?
                      >
                      > Gerald
                      >
                      First, let me make a correction. I said I exposed my plates for one
                      minute and twenty seconds to one and a half seconds....that should be
                      ..."to ONE AND A HALF MINUTES."

                      Beat me with a wet noodle if I'm halucinating, but the less time you
                      expose the pp plate the shallower the "etch" will be.

                      Everything I do with intaglio would have to be reversed for relief.
                      Where shallow plates work best(for me)for intaglio, deeper etched
                      plates would be better for relief. Where my inked areas print from
                      the depressions of the plates, in relief the ink is on the surface of
                      the raised areas of the plate. (I'm just figuring this out in my own
                      head.) So first I'd have to reverse my black and white areas on my
                      transparency.

                      Next, with detailed high contrast line art, I still don't know that
                      I'd go with totally intense black. I am getting theoretical now,
                      which isn't good, because I know there are folks out there who do
                      photopolymer plates on letterpresses quite often and know more than I
                      do. But what I feel comfortable saying is that in my experience with
                      "sun plates," I haven't ever exposed for more than one minute and
                      thirty seconds and have received a deep enough etch for relief. It is
                      a matter of whether intense black or a black that looks more like
                      purple gray on the transparency would better allow for more detail to
                      survive.

                      I reduce my black intensity in Photoshop using the "levels" filter
                      before printing to a transparency.

                      I still would not rince for more than a minute....at least with the
                      brand of sun plate sold by Daniel Smith. I do not know who
                      manufactures those plates.

                      Taking into account variability in the kind of artwork and personal
                      preference, test strips are the way to go.

                      Aurora Oberloh
                      Mossgate Private Press
                      Phoenix, AZ
                    • Gerald Lange
                      ... Hi Hmmm. Works the opposite with relief. The underlying structure begins to grow upward (shallower) as the exposure time lengthens. Seems odd but that s
                      Message 10 of 12 , Dec 5, 2002
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                        >
                        > Beat me with a wet noodle if I'm halucinating, but the less time you
                        > expose the pp plate the shallower the "etch" will be.
                        >

                        Hi

                        Hmmm. Works the opposite with relief. The underlying structure begins
                        to grow upward (shallower) as the exposure time lengthens. Seems odd
                        but that's the way it apparently works. The molecular connections
                        between the unexposed and exposed areas of the photopolymer begin to
                        link. A process called halation. Useful for halftones and other fine
                        detail as the supporting structure is better. The halation process is
                        halted by post-exposure. In the old days of photopolymer you needed to
                        "back-expose" to ensure the bottom of the plate became an
                        anti-halation layer. All sheet based photopolymer now comes all ready
                        prepared in this manner. At least that's my understanding of it.

                        Maybe there is a washout difference here? If you washout a fine detail
                        for too long, such as for instance, a separated rule, it will begin to
                        erode at the anti-halation layer.

                        I know we are discussing processes that are essentially the reverse of
                        each other but this does not make sense to me. Unless, of course,
                        everything I think I know about this is completely wrong. Its happened
                        before!!!

                        Gerald
                      • riverrider2
                        Thanks to all who replied. The response was decidedly mixed regarding the merits of hand processing. Some fully advocating it, while others advising against
                        Message 11 of 12 , Dec 6, 2002
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                          Thanks to all who replied. The response was decidedly mixed
                          regarding the merits of hand processing. Some fully advocating it,
                          while others advising against it. Being the dedicated DIYer that I
                          am, I'm going to start by having my plates professionally done, then
                          experiment with easy graphics to see how well I can make them on my
                          own. If it works, I save money and have unlimited tiem flexibility.
                          If not, I trash a few plates. I'll have fun either way.

                          Steve
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