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12873Re: [PPLetterpress] Re: Laser Engraved Photopolymer Plates

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  • Scott Rubel
    Oct 23, 2011
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      Gerald,

      Good thinking about all this. I certainly would want it to be a
      minimum of 2400, for one thing, but I have not known how to think
      about the other disadvantages.

      The thing that I hope for when I think about the potential of laser is
      straight sides to the raised type. I don't I understand why there
      would be a limit to the depth in a counter as opposed to any other
      part. My knowledge of lasers is based on mostly half- or 3/4-witted
      speculation mixed with fantasy, which is why I do not understand your
      last paragraph, but I trust your assessment.

      --Scott

      On Oct 22, 2011, at 10:57 PM, Gerald Lange wrote:

      > Scott
      >
      > I suspect that if cut just short of the floor of the plate rather
      > than down to the backing there would be no problem with the steel
      > reflecting. A more significant concern would be cutting through the
      > pre-exposed floor as plate stability would be sacrificed. Actually,
      > with this technique, the thinner the plate the better. All that
      >
      > I assume the identity of the plates themselves and the correct
      > timing for the exposure is a minor problem. 1200 dpi is still not
      > good enough, basically high-end laser printer quality. Imagesetter
      > quality at a minimum of 2400 dpi would be needed to match current
      > film based exposure.
      >
      > A major concern would be maintaining relative reverse relief depth,
      > which is fairly uniform when exposing photopolymer plates specified
      > for letterpress applications, no matter what the thickness of plate.
      > For instance, the relief depth of the counter of a small point size
      > lowercase e or o is not going to be open to the depth of the floor
      > of the plate. It is halted with maximum exposure at a specific
      > range, about .30 mm; relief depth is not uniform [which is actually
      > the best technical argument refuting the practice of extreme
      > impression]. I don't see how this could be controlled with a laser
      > cutter.
      >
      > Gerald
      > http://BielerPress.blogspot.com
      >
      >
      > --- In PPLetterpress@yahoogroups.com, Scott Rubel <scott@...> wrote:
      >>
      >> The website days it goes to 1200 dpi. If the coordinate tracking is
      >> accurate as it cuts, that should render pretty good six point type.
      >>
      >> It is hard to tell the quality of the laser, but I think I will ask
      >> them for a sample of steel backed polymer. I wonder how that works
      >> without the steel acting like a mirror.
      >>
      >> These laser beams can be unbelievable thin, if they are high quality.
      >> I work at a place where we make giant cameras for giant telescopes,
      >> and we order custom "slit masks" which are large sheets of aluminum
      >> with thousands of precision placed cuts in them. The cuts aren't much
      >> thicker than a hair, and you would think the laser is just moving
      >> along a path and cutting the slit, but in reality it cuts out the
      >> shape of the slit and almost microscopic blanks fall out of the metal
      >> every time a slit is cut. So if this Epilog Legend 36EXT machine is
      >> high quality, I would think six point type should work fine.
      >>
      >> --Scott
      >>
      >> On Oct 22, 2011, at 2:31 PM, Peter Fraterdeus wrote:
      >>
      >>>
      >>>
      >>> I'm interested in how well these desktop lasers can render type
      >>> below 6 points.
      >>> We run a LOT of business cards, many of which were designed for
      >>> mice, apparently ;-)
      >>>
      >>> Not ready to get rid of my Interflex platemaker yet!
      >>>
      >>> P
      >>>
      >>> Peter Fraterdeus
      >>> Exquisite letterpress takes time™
      >>> http://slowprint.com/
      >>> tweet: @slowprint
      >>>
      >>> IdeasWords : Idea Swords
      >>> Communication Strategy
      >>> Semiotx.com @ideaswords
      >>>
      >>> On 22 Oct 2011, at 2:40 PM, Silber MaiKätzchen wrote:
      >>>
      >>>>
      >>>>
      >>>> What number, thickness and brand plate are you
      >>>> using?
      >>>>
      >>>> I use a Epilog Legend 36EXT with a 120W laser, I
      >>>> am using a plate now that I like that comes with
      >>>> a steel or poly backing. It takes me eight minutes
      >>>> to do a 6X9" plate from Cobalt, their AccuLaze in
      >>>> 11 pt.
      >>>>
      >>>> MaiKätzchen
      >>>>
      >>>> Dum loquimur, fugerit invida Aetas:
      >>>> Carpe diem!
      >>>> quam minimum credula postero!
      >>>>
      >>>> Horace
      >>>> Odes Book I
      >>>>
      >>>>
      >>>> From: Gerald Lange <Bieler@...>
      >>>> To: PPLetterpress@yahoogroups.com
      >>>> Sent: Fri, October 21, 2011 11:50:01 PM
      >>>> Subject: [PPLetterpress] RE: Laser Engraved Photopolymer Plates
      >>>>
      >>>> Of potential interest is this thread from Briar Press Discussions:
      >>>>
      >>>> http://www.briarpress.org/27881
      >>>>
      >>>> Gerald
      >>>>
      >>>>
      >>>>
      >>>> ------------------------------------
      >>>>
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      >>>>
      >>>>
      >>>>
      >>>>
      >>>>
      >>>
      >>>
      >>>
      >>>
      >>
      >
      >
      >
      >
      > ------------------------------------
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