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[PPLetterpress] Re: Polymer Home Exposure

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  • Kent Manske
    Rod, your info to Katie was informative. I have not had the short exposure times that you have with the F20T12BLB, 24 , 20 watt bulb. I just build a box with 6
    Message 1 of 6 , Jan 27, 2003
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      Rod, your info to Katie was informative.

      I have not had the short exposure times that you have with the
      F20T12BLB, 24", 20 watt bulb. I just build a box with 6 tubes. Using
      both A&V and Boxcar plates, my exposure was more like 10 minutes (to
      hold 6 pt Bodoni serifs with hand wash) and 25 minutes to get step 16
      on a Stofer (?) scale.

      A phone call to Phillips informed me that the BLB (purple blacklite)
      has a uv filter on it. Their BL (white tube blacklite) does not. I've
      just ordered the BL bulbs and will run more exposure tests next
      weekend with hopes to reduce the required exposure time.

      Recap:
      Phillips F20T12BLB, 24", 20 watt bulb (purple blacklite), available
      at Home Depot and Wallmart.
      Phillips F20T12BL, 24", 20 watt bulb (white tube blacklite),
      available at Bulbs.com

      Rod, let me know if you think I've errored somewhere in my process.

      Thanks, Kent


      Katie

      For small plates with line art and type
      the weight of 1/4" plate glass will work
      so you don't have to use a vacuum frame.
      Ordinary blacklight fluorescent bulbs held
      in a striplight works fine. WalMart even
      sells them. Look for F20T12BLB which is
      a 24" 20 watt bulb. With the bulb about 3
      inches above the glass an exposure of 40
      to 60 seconds should be a good starting
      point. Each bulb will expose about 2" of
      plate width. So a 2 bulb fixtures will
      expose a 4" wide plate. Shouldn't cost
      more than $50.

      We prefer liquid photopolymer in our
      print shop since it washes out in less
      than a minute, whereas sheet photopolymers
      take at least 5 minutes, which gets old
      pretty fast for hand processing. Another
      advantage for liquid photopolymers is
      the plate thickness can be changed by the
      thickness of the bearers between the glass.
      We make dies from 1/16" to 3/16" thick.

      Our main use for these dies is for
      imprinting wooden tokens and have found
      that the 40 durometer dies make a better
      impression and conform to the texture of
      the wood.

      Hope this helps.

      Rod Grantham
      www.granthams.com



      --
      ______________________________
      Kent Manske
      PreNeo Press
      www.preneo.com
    • Rodney Grantham <granthams@wiktel.com>
      ... Using ... (to ... 16 ... blacklite) ... I ve ... Hi Kent The difference in exposure times could be due to several variables. The distance from the bulbs to
      Message 2 of 6 , Jan 27, 2003
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        --- In PPLetterpress@yahoogroups.com, Kent Manske <kent@p...> wrote:
        > Rod, your info to Katie was informative.
        >
        > I have not had the short exposure times that you have with the
        > F20T12BLB, 24", 20 watt bulb. I just build a box with 6 tubes.
        Using
        > both A&V and Boxcar plates, my exposure was more like 10 minutes
        (to
        > hold 6 pt Bodoni serifs with hand wash) and 25 minutes to get step
        16
        > on a Stofer (?) scale.
        >
        > A phone call to Phillips informed me that the BLB (purple
        blacklite)
        > has a uv filter on it. Their BL (white tube blacklite) does not.
        I've
        > just ordered the BL bulbs and will run more exposure tests next
        > weekend with hopes to reduce the required exposure time.
        >
        > Recap:
        > Phillips F20T12BLB, 24", 20 watt bulb (purple blacklite), available
        > at Home Depot and Wallmart.
        > Phillips F20T12BL, 24", 20 watt bulb (white tube blacklite),
        > available at Bulbs.com
        >
        > Rod, let me know if you think I've errored somewhere in my process.
        >
        > Thanks, Kent

        Hi Kent

        The difference in exposure times could be due to several
        variables. The distance from the bulbs to the plate, the
        voltage supplied to your bulbs and the type of plate
        material. We have our bulbs about 3" from the plate. Line
        voltage effects exposure times. On a dedicated circuit,
        so there is no voltage variation, our line voltage is 119.
        We are using a metal backed sheet polymer from the Louis
        Melind Company.

        If the specifications supplied with your plate material
        recommend a step 16 on a 21 step Stouffer platemakers
        guide, your setup may need a longer exposure. Sounds like
        you're on the right track.

        From our experience with photopolymer there is no difference
        in exposure times between the BL or BLB bulbs, in fact
        there is also a 350BL bulb. The numbers are the same
        on Phillips, Sylvania and GE bulbs.

        On another note, we also have a NuArc fliptop with carbon
        arcs and have found the exposure times need to be about
        4 minutes with this material.

        Regards,

        Rod Grantham
      • Katie Harper
        Thanks to everyone who wrote about home units for exposing polymer plates. The workshop was on Saturday, so I didn t have time to build a home exposure unit. I
        Message 3 of 6 , Jan 27, 2003
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          Thanks to everyone who wrote about home units for exposing polymer plates.
          The workshop was on Saturday, so I didn't have time to build a home exposure
          unit. I had bought a 250w photoflood bulb just in case the weather forced
          us indoors. I had no idea of the exposure time, but it probably would have
          been quite lengthy. Anyway, the weather cooperated nicely for us to make our
          exposure outdoors in bright sunlight for two minutes (I think it actually
          got up to 30 that day, a veritable heat wave around here...) I could not
          have asked for a more successful trial, and this was using a very quick 'n'
          dirty "negative" made by running transparency film through my laser printer.
          The workshop participants were suitably impressed as we proofed the plate
          and found it identical to the original (small squiggly lines). It worked so
          well it was a little hard for me to make the usual case about how one can
          do home processing for experimental stuff, but one really needs to have
          plates made professionally for consistently fine detail...

          Now that the workshop is over, I'm going to build my own home unit. I have a
          vacuum frame that was given to me ages ago, but it no longer has the vacuum
          motor. Any idea where I can get hold of that?




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





          > From: "Rodney Grantham <granthams@...>" <granthams@...>
          > Reply-To: PPLetterpress@yahoogroups.com
          > Date: Mon, 27 Jan 2003 17:12:42 -0000
          > To: PPLetterpress@yahoogroups.com
          > Subject: [PPLetterpress] Re: Polymer Home Exposure
          >
          > --- In PPLetterpress@yahoogroups.com, Kent Manske <kent@p...> wrote:
          >> Rod, your info to Katie was informative.
          >>
          >> I have not had the short exposure times that you have with the
          >> F20T12BLB, 24", 20 watt bulb. I just build a box with 6 tubes.
          > Using
          >> both A&V and Boxcar plates, my exposure was more like 10 minutes
          > (to
          >> hold 6 pt Bodoni serifs with hand wash) and 25 minutes to get step
          > 16
          >> on a Stofer (?) scale.
          >>
          >> A phone call to Phillips informed me that the BLB (purple
          > blacklite)
          >> has a uv filter on it. Their BL (white tube blacklite) does not.
          > I've
          >> just ordered the BL bulbs and will run more exposure tests next
          >> weekend with hopes to reduce the required exposure time.
          >>
          >> Recap:
          >> Phillips F20T12BLB, 24", 20 watt bulb (purple blacklite), available
          >> at Home Depot and Wallmart.
          >> Phillips F20T12BL, 24", 20 watt bulb (white tube blacklite),
          >> available at Bulbs.com
          >>
          >> Rod, let me know if you think I've errored somewhere in my process.
          >>
          >> Thanks, Kent
          >
          > Hi Kent
          >
          > The difference in exposure times could be due to several
          > variables. The distance from the bulbs to the plate, the
          > voltage supplied to your bulbs and the type of plate
          > material. We have our bulbs about 3" from the plate. Line
          > voltage effects exposure times. On a dedicated circuit,
          > so there is no voltage variation, our line voltage is 119.
          > We are using a metal backed sheet polymer from the Louis
          > Melind Company.
          >
          > If the specifications supplied with your plate material
          > recommend a step 16 on a 21 step Stouffer platemakers
          > guide, your setup may need a longer exposure. Sounds like
          > you're on the right track.
          >
          > From our experience with photopolymer there is no difference
          > in exposure times between the BL or BLB bulbs, in fact
          > there is also a 350BL bulb. The numbers are the same
          > on Phillips, Sylvania and GE bulbs.
          >
          > On another note, we also have a NuArc fliptop with carbon
          > arcs and have found the exposure times need to be about
          > 4 minutes with this material.
          >
          > Regards,
          >
          > Rod Grantham
          >
          >
          >
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