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Re: [PPLetterpress] Washing out plates by hand

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  • Ed Inman
    There are so many variables in exposure units and materials that there is unfortunately no one size fits all answer when it comes to hand processing. Water
    Message 1 of 8 , Nov 14, 2010
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      There are so many variables in exposure units and materials that there is unfortunately no "one size fits all" answer when it comes to hand processing.

      Water temp, bristle hardness, scrubbing method, etc. are indeed all variables to consider, but...
      In my experience your likely bigger variables are: 1. exposure time; and 2. negative density.
      I would suggest you use only very dense, professionally-made Imagesetter or ortho lith camera negatives and gradually try increasing your plate exposure time. (The most common problems, IMO, result from people trying to use overhead transparency "negatives" made in ink jet printers.)

      I expose and process my own ortho lith negatives (if you have even rudimentary darkroom skills they are easy to make) and use the 145HSB steel backed plates with a 2.5 minute exposure. I have found I can easily wash the plates 7 to 8 minutes in the sink before there is any threat of damage to fine points. This is generally ample time to process a 5" x 7" plate or a little larger.

      good luck,
      Ed


      -----Original Message-----
      >From: amy <aborezo@...>
      >Sent: Nov 14, 2010 9:40 AM
      >To: PPLetterpress@yahoogroups.com
      >Subject: [PPLetterpress] Washing out plates by hand
      >
      >Hello,
      >
      >I have access to an exposure unit that has no washout unit and have been washing out plates by hand. I was finding that it was taking longer than recommended to wash out plates and so fine lines would start to break down. Changing the temp of the water to slightly warmer seems to have helped somewhat. What is it that gets the soft plate material to clear from the plate quickly? should I be scrubbing vigorously or not? Is it just time? Does water temp. effect anything? hardness of bristles on the brush? Does a constant jet of water over the plate help?
      >
      >I'm using the 94FL plastic backed plate from Boxcar.
      >
      >any advice welcome. Thank you.
      >
      >Amy Borezo
      >www.shelterbookworks.com
      >
      >
      >
      >
      >------------------------------------
      >
      >Yahoo! Groups Links
      >
      >
      >
    • typetom@aol.com
      Hi Amy, I hand wash steel-backed Miraclon MS152 photopolymer plates. As I understand the process, UV exposure changes the chemical structure of the polymer
      Message 2 of 8 , Nov 14, 2010
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        Hi Amy,
        I hand wash steel-backed Miraclon MS152 photopolymer plates.
         
        As I understand the process, UV exposure changes the chemical structure of the polymer making it no longer soluble in water. Since the exposure starts on the surface, the printing detail on the surface would harden first, while the base of the polymer material may yet only be partially affected. This means that break-up of the plate during washout occurs as the base material softens. Typical problems are separation of the surface from the base, or weakness in the base support which allows fine lines to become wavy or broken.
         
        The answer for such problems is to limit the time in the water. Since the surface is hardened most completely, aggressive brushing at the start is fine. The longer in the water, the more the base material begins to soften. Thus, vigorous brushing is more likely to cause damage as the process continues. With my material and exposure time etc, I stop washout at about four minutes whether or not the plate is completely clean down to the metal.
         
        Processing larger plates by hand is more difficult because it takes longer to brush a larger surface. Machine washout has the advantage of a larger brush, with uniform continuous brushing over the whole surface. Hand washout of a large plate requires discipline about the time limit!
         
        Water temperature does affect the speed with which unexposed material will dissolve, but the practical range is rather broad. I use water that is warm to the touch but not hot. Too cold does slow it down, but I've never felt a need to measure the temperature.
         
        A water jet probably is not a good answer, as that is uncontrolled pressure that might undercut the softer base material. In general, the brush is not a scraping process but an agitation to remove material that has become softened by the water. Without the brush, the unexposed material would become soft as it absorbs water, but it would remain in place; the brush by itself does not remove the material until it is loosened by the water. So it is an active agitation of brush as the material is affected by the water, limited by the remaining support of material at the base.
         
        The other critical factor is exposure time: a longer exposure will harden the base material further, thus strengthening support for fine lines or dots. But it also can expand the shoulders of the plate and make the printed image more bold. Over exposure will cause fine counter spaces and white lines to fill as more base material is hardened.
         
        And any negative that is not opaque enough may allow material to partially harden where not intended, resulting in a spotty washout as the partially exposed material does not dissolve evenly in the water.
         
        I hope this helps! 
        Tom
         
        Tom Parson/ Now It's Up To You
        157 S Logan, Denver CO 80209
        (303) 777-8951 - home & letterpress printshop
        (720) 480-5358 - cranky cellphone
        typetom@...
         
         

        In a message dated 11/14/2010 8:40:40 A.M. Mountain Standard Time, aborezo@... writes:
        Hello,

        I have access to an exposure unit that has no washout unit and have been washing out plates by hand. I was finding that it was taking longer than recommended to wash out plates and so fine lines would start to break down. Changing the temp of the water to slightly warmer seems to have helped somewhat. What is it that gets the soft plate material to clear from the plate quickly? should I be scrubbing vigorously or not? Is it just time? Does water temp. effect anything? hardness of bristles on the brush? Does a constant jet of water over the plate help?

        I'm using the 94FL plastic backed plate from Boxcar.

        any advice welcome. Thank you.

        Amy Borezo
        www.shelterbookworks.com




         
      • heytrollop
        Hi, I wash out all my plates by hand. You can get the washout brush from boxcar if you don t already have one. I use water between 70 and 80 degrees, I usually
        Message 3 of 8 , Nov 14, 2010
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          Hi,

          I wash out all my plates by hand.
          You can get the washout brush from boxcar if you don't already have one.
          I use water between 70 and 80 degrees, I usually aim for 80 ish when I set it up expose my plate and the water has cooled a little by then.

          I scrub out in a figure 8 motion. For not more than 5 minutes. After than you may have problems with losing details.
          (for photogravure plates it's a minute)

          Also if your plates are old you can lose detail. Someone also mentioned a while back, exposing the back for 30 seconds to kind of set things. I haven't tried this yet but it seems sensible.

          Also I've found if you have the deeper relief plates and you're having washout issues you can not scrub it all the way out. It isn't optimal, and might be an issue if you are printing with a deep impression.

          Also we have a homemade "baking" unit which is essentially a hair dryer and a vented box. I make sure my plates are well above and as far as possible from the air intake so that during baking I don't get wavy lines in the fine detail.

          best,
          Raven

          --- In PPLetterpress@yahoogroups.com, Ed Inman <edinman@...> wrote:
          >
          > There are so many variables in exposure units and materials that there is unfortunately no "one size fits all" answer when it comes to hand processing.
          >
          > Water temp, bristle hardness, scrubbing method, etc. are indeed all variables to consider, but...
          > In my experience your likely bigger variables are: 1. exposure time; and 2. negative density.
          > I would suggest you use only very dense, professionally-made Imagesetter or ortho lith camera negatives and gradually try increasing your plate exposure time. (The most common problems, IMO, result from people trying to use overhead transparency "negatives" made in ink jet printers.)
          >
          > I expose and process my own ortho lith negatives (if you have even rudimentary darkroom skills they are easy to make) and use the 145HSB steel backed plates with a 2.5 minute exposure. I have found I can easily wash the plates 7 to 8 minutes in the sink before there is any threat of damage to fine points. This is generally ample time to process a 5" x 7" plate or a little larger.
          >
          > good luck,
          > Ed
          >
          >
          > -----Original Message-----
          > >From: amy <aborezo@...>
          > >Sent: Nov 14, 2010 9:40 AM
          > >To: PPLetterpress@yahoogroups.com
          > >Subject: [PPLetterpress] Washing out plates by hand
          > >
          > >Hello,
          > >
          > >I have access to an exposure unit that has no washout unit and have been washing out plates by hand. I was finding that it was taking longer than recommended to wash out plates and so fine lines would start to break down. Changing the temp of the water to slightly warmer seems to have helped somewhat. What is it that gets the soft plate material to clear from the plate quickly? should I be scrubbing vigorously or not? Is it just time? Does water temp. effect anything? hardness of bristles on the brush? Does a constant jet of water over the plate help?
          > >
          > >I'm using the 94FL plastic backed plate from Boxcar.
          > >
          > >any advice welcome. Thank you.
          > >
          > >Amy Borezo
          > >www.shelterbookworks.com
          > >
          > >
          > >
          > >
          > >------------------------------------
          > >
          > >Yahoo! Groups Links
          > >
          > >
          > >
          >
        • heytrollop
          Also one more important detail you should not apply pressure to the brush as you wash out. Just use the weight of the brush as you move it with your hand.
          Message 4 of 8 , Nov 14, 2010
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            Also one more important detail you should not apply pressure to the brush as you wash out. Just use the weight of the brush as you move it with your hand.

            --- In PPLetterpress@yahoogroups.com, "heytrollop" <heytrollop@...> wrote:
            >
            > Hi,
            >
            > I wash out all my plates by hand.
            > You can get the washout brush from boxcar if you don't already have one.
            > I use water between 70 and 80 degrees, I usually aim for 80 ish when I set it up expose my plate and the water has cooled a little by then.
            >
            > I scrub out in a figure 8 motion. For not more than 5 minutes. After than you may have problems with losing details.
            > (for photogravure plates it's a minute)
            >
            > Also if your plates are old you can lose detail. Someone also mentioned a while back, exposing the back for 30 seconds to kind of set things. I haven't tried this yet but it seems sensible.
            >
            > Also I've found if you have the deeper relief plates and you're having washout issues you can not scrub it all the way out. It isn't optimal, and might be an issue if you are printing with a deep impression.
            >
            > Also we have a homemade "baking" unit which is essentially a hair dryer and a vented box. I make sure my plates are well above and as far as possible from the air intake so that during baking I don't get wavy lines in the fine detail.
            >
            > best,
            > Raven
            >
            > --- In PPLetterpress@yahoogroups.com, Ed Inman <edinman@> wrote:
            > >
            > > There are so many variables in exposure units and materials that there is unfortunately no "one size fits all" answer when it comes to hand processing.
            > >
            > > Water temp, bristle hardness, scrubbing method, etc. are indeed all variables to consider, but...
            > > In my experience your likely bigger variables are: 1. exposure time; and 2. negative density.
            > > I would suggest you use only very dense, professionally-made Imagesetter or ortho lith camera negatives and gradually try increasing your plate exposure time. (The most common problems, IMO, result from people trying to use overhead transparency "negatives" made in ink jet printers.)
            > >
            > > I expose and process my own ortho lith negatives (if you have even rudimentary darkroom skills they are easy to make) and use the 145HSB steel backed plates with a 2.5 minute exposure. I have found I can easily wash the plates 7 to 8 minutes in the sink before there is any threat of damage to fine points. This is generally ample time to process a 5" x 7" plate or a little larger.
            > >
            > > good luck,
            > > Ed
            > >
            > >
            > > -----Original Message-----
            > > >From: amy <aborezo@>
            > > >Sent: Nov 14, 2010 9:40 AM
            > > >To: PPLetterpress@yahoogroups.com
            > > >Subject: [PPLetterpress] Washing out plates by hand
            > > >
            > > >Hello,
            > > >
            > > >I have access to an exposure unit that has no washout unit and have been washing out plates by hand. I was finding that it was taking longer than recommended to wash out plates and so fine lines would start to break down. Changing the temp of the water to slightly warmer seems to have helped somewhat. What is it that gets the soft plate material to clear from the plate quickly? should I be scrubbing vigorously or not? Is it just time? Does water temp. effect anything? hardness of bristles on the brush? Does a constant jet of water over the plate help?
            > > >
            > > >I'm using the 94FL plastic backed plate from Boxcar.
            > > >
            > > >any advice welcome. Thank you.
            > > >
            > > >Amy Borezo
            > > >www.shelterbookworks.com
            > > >
            > > >
            > > >
            > > >
            > > >------------------------------------
            > > >
            > > >Yahoo! Groups Links
            > > >
            > > >
            > > >
            > >
            >
          • amy borezo
            Thanks for all of the advice. Everything was most helpful. I get film output from an imagesetter when possible, but sometimes I double up transparency
            Message 5 of 8 , Nov 15, 2010
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              Thanks for all of the advice. Everything was most helpful. I get film output from an imagesetter when possible, but sometimes I double up transparency film...not ideal, I know. Adding a step in the darkroom is not practical at this time. These plates are for my students. When something is critical for my own artwork, I usually get Boxcar to make the plate, though I'm getting better at making the plates myself :).

              Great to know about water temp and bristle/brushing action.

              happy printing,
              --
              Amy Borezo


            • Eric
              I suspect that a plate s full resitance to water is dependant on how much post-exposure is given. Double the main exposure is a rule of thumb, but main
              Message 6 of 8 , Nov 15, 2010
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                I suspect that a plate's full resitance to water is dependant on how much post-exposure is given. Double the main exposure is a rule of thumb, but main exposures can vary quite a bit. The main exposure allows a little latitude for washout times, but not a lot. When the plate has been wet a maximum amount of time, you can dry the plate and then proceed with more washout. For example, when you see a straight line begin to go wavy, stop immediately before any damage happens to the material. Dry the plate and then go back into the bath if more washout is needed. It is even possible to proof the plate and then go back into the bath as long as you haven't post-exposed it.
                I washed out by hand for many years, and still do if I just have one or two small plates. I found better results by imitating the machine process. That is, I filled a 9x12 photo tray with brushes, and made a plate carrier out of sheet aluminum, handles, and sheet magnet. Then I use circular and figure-eight motions alternately, and the results are a lot more consistant than when I was moving the brush. The bristles support the whole carrier and you can't tip or apply too much pressure. Even so the outer edges of any image are more prone to damage when processd by hand than by machine.
                --Eric Holub, SF
              • Bryce Erickson
                filled a 9x12 photo tray with brushes, and made a plate carrier out of sheet aluminum, handles, and sheet magnet. Then I use circular and figure-eight
                Message 7 of 8 , Nov 15, 2010
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                  "filled a 9x12 photo tray with brushes, and made a plate carrier out of sheet aluminum, handles, and sheet magnet. Then I use circular and figure-eight motions alternately, and the results are a lot more consistant than when I was moving the brush."

                  Eric and group,
                  I am doing something similar.  I bought two of Boxcar's brushes and a small sheet of magnetic vinyl (fridge magnet stuff).  Used a waterproof adhesive to attach the vinyl to the brush handles and to the bottom of a darkroom tray.  Side-by-side, the two brushes provide about 7 by 7 inch area.  Held in place by the mag. vinyl, they seem to resist the shear pressure and stay put.  Using all 10 fingers to hold and apply even pressure to the back of the plate, I go up-and-down, side-to-side and circular.  Then I turn the plate orientation 90 degrees and repeat the brushing.  The plate is easy to pull out of the tray to check progress.

                  Bryce Erickson
                  Saskatoon SK Canada

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