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Re: [PPLetterpress] Re: resolution

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  • Nicolas Goosen
    Iohannes, Sorry, I stand corrected.
    Message 1 of 15 , Sep 1, 2008
      Iohannes,

      Sorry, I stand corrected.
      > ('lpi', not 'dpi' by the way)
      >
    • Iohannes Daubmannus
      ... 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
      Message 2 of 15 , Sep 1, 2008
        > 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?
      • 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 3 of 15 , Sep 1, 2008
          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 4 of 15 , Sep 1, 2008
            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 5 of 15 , Sep 1, 2008
              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 6 of 15 , Sep 2, 2008
                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 7 of 15 , Sep 2, 2008
                  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 8 of 15 , Sep 2, 2008
                    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 9 of 15 , Sep 2, 2008
                      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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