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Re: [PPLetterpress] Re: resolution

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  • Gerald Lange
    Iohannes This is from a Toyobo Printight promo, not a technical sheet: Halftone resolution: 150 lpi Min. isolated dot: .0075 Min. isolated line: .0015 Real
    Message 1 of 15 , Sep 1, 2008
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      Iohannes

      This is from a Toyobo Printight promo, not a technical sheet:

      Halftone resolution: 150 lpi
      Min. isolated dot: .0075
      Min. isolated line: .0015

      Real resolution would be a bit of a misnomer but yes, certainly, test it
      out, and let us know your findings.

      Note that you will experience gain at the film negative stage, you will
      experience gain related to increased "printing pressure," and you will
      experience gain as the result of increasing ink film coverage. So there
      are a lot of variables that can throw your readings off.

      I have a number of technical test reports from Toyobo and the gain
      revealed from those is surprising high. Anything you can do at the
      prepress stage to counter this is your best option.

      Gerald
      http://BielerPress.blogspot.com

      Iohannes Daubmannus wrote:
      >> on the best of plates,
      >> fine lines accurately at .0015"
      >> and isolated dots .0075" in diameter.
      >>
      >
      > Gerald, thank you, it's just I need.
      >
      > But I'm not sure...
      > Can fine line size be smaller than isolated dot size?
      > E.g. it tech specs of Toyobo Printight plates shown
      > lines 0.1 mm (.004"), dots 0.02 mm (0.0008")
      >
      > Anyway if I make a test chart with stroke patterns from 0.01 mm (.2
      > pt, .0004") to 0.5 mm (.02"), I'll see the real resolution on my plate
      > and on my press. Am I right?
      >
      > ------------------------------------
      >
      >
    • Scott Rubel
      Whatever anyone says about resolution, my real world test was this. I scanned some illustrations of William Blake s fine line illustrations from Night
      Message 2 of 15 , Sep 1, 2008
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        Whatever anyone says about resolution, my real world test was this.

        I scanned some illustrations of William Blake's fine line
        illustrations from "Night Thoughts" and had polymer plates made and
        printed them on my C&P. I doubt that anyone could tell the difference
        between my reproduction and the Dover reproduction.

        That's enough information for me.

        --Scott Rubel

        On Sep 1, 2008, at 9:58 AM, Gerald Lange wrote:

        > Iohannes
        >
        > This is from a Toyobo Printight promo, not a technical sheet:
        >
        > Halftone resolution: 150 lpi
        > Min. isolated dot: .0075
        > Min. isolated line: .0015
        >
        > Real resolution would be a bit of a misnomer but yes, certainly,
        > test it
        > out, and let us know your findings.
        >
        > Note that you will experience gain at the film negative stage, you
        > will
        > experience gain related to increased "printing pressure," and you will
        > experience gain as the result of increasing ink film coverage. So
        > there
        > are a lot of variables that can throw your readings off.
        >
        > I have a number of technical test reports from Toyobo and the gain
        > revealed from those is surprising high. Anything you can do at the
        > prepress stage to counter this is your best option.
        >
        > Gerald
        > http://BielerPress.blogspot.com
        >
        > Iohannes Daubmannus wrote:
        >>> on the best of plates,
        >>> fine lines accurately at .0015"
        >>> and isolated dots .0075" in diameter.
        >>>
        >>
        >> Gerald, thank you, it's just I need.
        >>
        >> But I'm not sure...
        >> Can fine line size be smaller than isolated dot size?
        >> E.g. it tech specs of Toyobo Printight plates shown
        >> lines 0.1 mm (.004"), dots 0.02 mm (0.0008")
        >>
        >> Anyway if I make a test chart with stroke patterns from 0.01 mm (.2
        >> pt, .0004") to 0.5 mm (.02"), I'll see the real resolution on my
        >> plate
        >> and on my press. Am I right?
        >>
        >> ------------------------------------
        >>
        >>
        >
        >
        > ------------------------------------
        >
        > Yahoo! Groups Links
        >
        >
        >
      • Gerald Lange
        Iohannes The relief structure of photopolymer is unlike cast metal type and unlike photomechanical chemical etching. The longer the exposure latitude, the
        Message 3 of 15 , Sep 1, 2008
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          Iohannes

          The relief structure of photopolymer is unlike cast metal type and
          unlike photomechanical chemical etching.

          The longer the exposure latitude, the shallower the relief between
          surface imaging. Isolated elements, dots, lines, would thus have less
          structural support. But an isolated line would have better support
          than an isolated dot.

          I have put some images up in the photo section here
          Photos>Bieler Press
          that show microphotography of halftone plates at 150lpi. Note the
          variance in slope and relief based on different exposure latitude.

          Gerald
          http://BielerPress.blogspot.com

          >
          > But I'm not sure...
          > Can fine line size be smaller than isolated dot size?
          > E.g. it tech specs of Toyobo Printight plates shown
          > lines 0.1 mm (.004"), dots 0.02 mm (0.0008")
          >
          >
        • Iohannes Daubmannus
          Gerald, thanks for your explanation! ... Now I thought: is a common resolution test with stroke patterns (like 1951 USAF
          Message 4 of 15 , Sep 2, 2008
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            Gerald, thanks for your explanation!

            > Isolated elements

            Now I thought: is a common resolution test with stroke patterns (like 1951 USAF
            http://en.wikipedia.org/wiki/1951_USAF_Resolution_Test_Chart) suitable
            to determine minimum size of _isolated_ objects?..
            I'll add lines and dots with triple thickness distance between.
          • Iohannes Daubmannus
            please, take a look at my chart for the test: http://www.bjorn.kiev.ua/letterpress/res_test.pdf values (widths and dots diameters) shown in postscript points.
            Message 5 of 15 , Sep 2, 2008
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              please, take a look at my chart for the test:
              http://www.bjorn.kiev.ua/letterpress/res_test.pdf
              values (widths and dots' diameters) shown in postscript points.
            • Nicolas Goosen
              Very nice! I was just reminded of the Resometer chart. Considering that the Resometer target is nearly $400 I d have to say that your chart rocks! -Nicolas
              Message 6 of 15 , Sep 2, 2008
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                Very nice!

                I was just reminded of the 'Resometer' chart. Considering that the
                Resometer target is nearly $400 I'd have to say that your chart rocks!

                -Nicolas

                > please, take a look at my chart for the test:
                > http://www.bjorn.kiev.ua/letterpress/res_test.pdf
                > values (widths and dots' diameters) shown in postscript points.
                >
              • Gerald Lange
                Iohannes This should work. I recall that BASF recommended printing a ruler in regard to stretch on cylinder mounted plates (just to ensure the math was
                Message 7 of 15 , Sep 2, 2008
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                  Iohannes

                  This should work. I recall that BASF recommended printing a ruler in
                  regard to stretch on cylinder mounted plates (just to ensure the math
                  was correct). So you are on a proven track.

                  Gerald
                  http://BielerPress.blogspot.com

                  Iohannes Daubmannus wrote:
                  > please, take a look at my chart for the test:
                  > http://www.bjorn.kiev.ua/letterpress/res_test.pdf
                  > values (widths and dots' diameters) shown in postscript points.
                  >
                  > ------------------------------------
                  >
                  >
                  >
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