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Photopolymer Optimization of letterforms

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  • David P. Wall
    Greetings all: I work for a printing company that specializes in printing (by offset lithography) 300 line-screen duotone and tritone images, where the
    Message 1 of 7 , Aug 21, 2001
      Greetings all:

      I work for a printing company that specializes in printing (by offset
      lithography) 300 line-screen duotone and tritone images, where the halftone
      dots need to be very sharp. The imagesetter settings that give us the
      sharpest dots can also make text faces printed in conjunction with the
      images appear to be a bit light and spindly (especially faces with fine
      hairlines such as Bodoni or Walbaum), so we often electronically "trap" or
      "spread" the text to beef it back up to its normal weight. When first
      experimenting with polymer letterpress several years ago, I discovered that
      there are also ways to "negative trap" or "choke" the type in QuarkXPress to
      compensate for ink squeeze and some of the vagaries of using a single master
      type pattern for multiple sizes of a computer typeface. The process is not
      quite as simple as spreading the text for offset printing, and I've found
      that not all film houses are interested in working through the somewhat
      strange parameters. But if you can find a film house that is willing to work
      with you, the results are remarkably satisfying.

      Has anyone else experimented with this process (or any means other than
      altering the letterforms with Fontographer or similar programs)?

      David Wall




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    • Gerald Lange
      Dear David Will this negative trapping technique work on large blocks of text type, page after page? or just display or headlines, etc? And of course, what are
      Message 2 of 7 , Aug 21, 2001
        Dear David

        Will this negative trapping technique work on large blocks of text
        type, page after page? or just display or headlines, etc?

        And of course, what are the "ways."

        Thanks for this, all best,

        Gerald

        "David P. Wall" <dpwall@h...> wrote:
        >When first
        > experimenting with polymer letterpress several years ago, I discovered that
        > there are also ways to "negative trap" or "choke" the type in QuarkXPress to
        > compensate for ink squeeze and some of the vagaries of using a single master
        > type pattern for multiple sizes of a computer typeface. The process is not
        > quite as simple as spreading the text for offset printing, and I've found
        > that not all film houses are interested in working through the somewhat
        > strange parameters.
      • dpwall@hotmail.com
        Gerald: Yes, you can negative-trap blocks of text-size type, or display type, or even rules, and probably some line art depending on how the line art image
        Message 3 of 7 , Aug 22, 2001
          Gerald:

          Yes, you can negative-trap blocks of text-size type, or display type,
          or even rules, and probably some line art depending on how the line
          art image files are formatted. Where multiple sizes of type appear on
          one page, you have the flexibility to apply a different trap to each
          size, so that you can even-out the overall color of the page.
          Basically (in QuarkXPress) you create a solid-colored background
          behind the text, trap the background to the text (by choking it in on
          the text), and then use a positive of the background (with the choked
          text knocked out of it) as a negative to make the polymer plate.
          Sounds simple, right? Maybe not, but once you get used to the way it
          works, it really is pretty simple (albeit somewhat more time-
          consuming than just sending an un-trapped file to the imagesetter).
          If you'd like to see some proofs of a test page trapped to varying
          degrees, let me know. I've still got a few sheets in my files.

          I've wondered for a long time if I was the only person bothered by
          the fat appearance of most polymer type. It is refreshing to hear
          in this discussion group that there are other people out there with
          similar concerns.

          With regards,

          Dave



          --- In PPLetterpress@y..., "Gerald Lange" <bieler@w...> wrote:
          > Dear David
          >
          > Will this negative trapping technique work on large blocks of text
          > type, page after page? or just display or headlines, etc?
          >
          > And of course, what are the "ways."
          >
          > Thanks for this, all best,
          >
          > Gerald
          >
        • Gerald Lange
          Dear David Thanks for the return post. I would very much like to see your sample output. I think letterform optimization is a crucial aspect of getting
          Message 4 of 7 , Aug 22, 2001
            Dear David

            Thanks for the return post. I would very much like to see your sample
            output. I think letterform optimization is a crucial aspect of getting
            photopolymer to print as if it were metal type. Lots of folks don't
            understand this and then blame the process. So thanks for bringing it
            back up.

            Gerald Lange
            The Bieler Press
            4216 1/4 Glencoe Avenue
            Marina del Rey, CA 90292

            All best

            Gerald

            dpwall@h... wrote:
            >

            ...I've wondered for a long time if I was the only person bothered by
            > the fat appearance of most polymer type. It is refreshing to hear
            > in this discussion group that there are other people out there with
            > similar concerns.
            >
            > With regards,
            >
            > Dave
          • dpwall@hotmail.com
            Gerald: The proofs are on their way, via USPS. I live in northern Vermont, so they probably won t arrive in your mailbox until the middle of next week. Dave
            Message 5 of 7 , Aug 23, 2001
              Gerald:

              The proofs are on their way, via USPS. I live in northern Vermont, so
              they probably won't arrive in your mailbox until the middle of next
              week.

              Dave


              --- In PPLetterpress@y..., "Gerald Lange" <bieler@w...> wrote:
              >
              >Thanks for the return post. I would very much like to see your
              >sample output. I think letterform optimization is a crucial aspect
              >of getting photopolymer to print as if it were metal type. Lots of
              >folks don't understand this and then blame the process. So thanks
              >for bringing it back up.
              >
            • Gerald Lange
              Dear David [Wall] Thanks for sending the proofs. These look quite good. I ve got some questions: Is the -.064 choke normative or maximum? How much further
              Message 6 of 7 , Aug 28, 2001
                Dear David [Wall]

                Thanks for sending the proofs. These look quite good. I've got some
                questions:
                Is the -.064 choke normative or maximum? How much further could you
                choke before you experience letterform breakup?
                I assume this is possible in PageMaker, Illustrator, InDesign as well,
                do you know?
                Does this effect leading or other page parameters; line length, text
                block measure, etc? From the proofs I'd quess not, correct?
                What are the difficulties encountered in explaining the trapping to
                the folks at the service bureau (film house)?

                Think this may be a useful technique. Thanks.

                Gerald

                David P. Wall wrote
                When first experimenting with polymer letterpress several years ago, I
                discovered that there are also ways to "negative trap" or "choke" the
                type in QuarkXPress to compensate for ink squeeze and some of the
                vagaries of using a single master type pattern for multiple sizes of a
                computer typeface. The process is not quite as simple as spreading the
                text for offset printing, and I've found that not all film houses are
                interested in working through the somewhat strange parameters. But if
                you can find a film house that is willing to work with you, the
                results are remarkably satisfying....
                .... you can negative-trap blocks of text-size type, or display or
                even rules, and probably some line art depending on how the art image
                files are formatted. Where multiple sizes of type appear one page, you
                have the flexibility to apply a different trap to size, so that you
                can even-out the overall color of the page. Basically (in QuarkXPress)
                you create a solid-colored background behind the text, trap the
                background to the text (by choking it in on the text), and then use a
                positive of the background (with the text knocked out of it) as a
                negative to make the polymer plate. Sounds simple, right? Maybe not,
                but once you get used to the way it works, it really is pretty simple
                (albeit somewhat more time-consuming than just sending an un-trapped
                file to the imagesetter). If you'd like to see some proofs of a test
                page trapped to varying degrees, let me know. I've still got a few
                sheets in my files....
                I've wondered for a long time if I was the only person bothered the
                fat appearance of most polymer type. It is refreshing to in this
                discussion group that there are other people out there similar
                concerns. Will this negative trapping technique work on large blocks
                of text...
              • dpwall@hotmail.com
                Gerald: ... The -.064 choke is neither normative nor maximum. It just happens to be what gave the best overall effect for that particular test page. For best
                Message 7 of 7 , Aug 29, 2001
                  Gerald:

                  I'm glad you like the proofs. In response to your questions:

                  > Is the -.064 choke normative or maximum?
                  The -.064 choke is neither normative nor maximum. It just happens to
                  be what gave the best overall effect for that particular test page.
                  For best results I think you should apply less choke to smaller sizes
                  of type, and more to the larger, and it bears some experimentation
                  with the amounts applied to different typefaces. I found that
                  the "gain" from my laser printer (relative to the high resolution of
                  an imagesetter) roughly mimics the gain from letterpress, and it is
                  therefore possible to experiment first with laser proofs before
                  wasting a lot of expensive film and plate material.

                  > How much further could you choke before you experience letterform
                  > breakup?
                  The amount of additional choke that can be applied depends both on
                  the specific typeface design, and on the size at which you are
                  reproducing it. Smaller types, and those with finer lines, will start
                  to break up before the larger sizes and heavier designs. Quark allows
                  a choke of up to -36 points---three whole picas!---which is obviously
                  far more latitude than we need for this purpose. In most cases I
                  would think an appropriate amount of choke for a text face would be
                  between -0.100 and -.008 points, depending on the size and the design.

                  > I assume this is possible in PageMaker, Illustrator, InDesign as
                  > well, do you know?
                  I do not have first-hand experience in trapping/choking with these
                  programs, but they undoubtedly must all have some sort of function
                  for addressing trapping of colors to one another. If so, they can
                  probably be adapted to choke the text the same way that it works in
                  Quark.

                  > Does this effect leading or other page parameters; line length,
                  > text block measure, etc?
                  The choking/trapping does not have any significant effect on line
                  length or text block size. It basically is just the reverse of the
                  gain that you get from ink squeeze on press.

                  > What are the difficulties encountered in explaining the trapping to
                  > the folks at the service bureau (film house)?
                  The problem that I encountered with one film house was just in trying
                  to make it clear to them what I wanted the final output to look like.
                  It can be confusing because what you need is positive film of the
                  colored background (this is what has the choked type knocked out of
                  it), which will end up looking kind of like a negative piece of film.
                  And of course, the film also needs to be right-reading/emulsion-up.
                  For most service bureaus it should not be a problem if you ask them
                  for RREU Positive film of the color channel. If they are outputting a
                  file that you prepared yourself, they should not need to do anything
                  with regard to the trapping/choking. (Note that you do not want film
                  for the black channel, even though this is technically the channel
                  with the type in it.)

                  I hope this is making some sense to everyone. It is much easier for
                  me to explain in person, where I can draw diagrams and use hand
                  gestures. I will gladly try to answer more questions if you have them.

                  With best regards,

                  David Wall
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