Loading ...
Sorry, an error occurred while loading the content.

Re: [PPLetterpress] Re: resolution

Expand Messages
  • Nicolas Goosen
    Yep, I m a total newbie to platen press operation so am not going to be attempting halftones anytime soon. (Or the complicated make-ready that precedes them.)
    Message 1 of 15 , Sep 1, 2008
    • 0 Attachment
      Yep, I'm a total newbie to platen press operation so am not going to
      be attempting halftones anytime soon. (Or the complicated make-ready
      that precedes them.)

      I do have some inspiration, however, in the form of a print that I
      ordered from PeriodPaper.com of an advert for Heidelberg platens
      apparently printed on an Original Heidelberg in 1930-something. In the
      foreground is an illustration of said platen and it printed beautifully!

      Can't hope just yet to be competing with Heidelberg themselves in
      print quality though...

      Nicolas


      On 31 Aug 2008, at 11:00 PM, Gerald Lange wrote:

      > Nicolas
      >
      > Well in terms of optimal printing conditions, and on the best of
      > plates, one could reproduce fine lines accurately at .0015", halftones
      > at 150-200 lpi, and isolated dots .0075" in diameter.
      >
      > Not with letterpress though. I use 150 lpi but that is pushing it.
      > Halftone work is probably best avoided as it requires sophisticated
      > prepress configuration, a specific type of paper, makeready, ink, and
      > a lot of attention to detail during presswork. If you are trying to
      > get it right. I use the old Lewis Roberts HT inks as they seem to hold
      > the best.
      >
      > Gerald
      > http://BielerPress.blogspot.com
      >
      > --- In PPLetterpress@yahoogroups.com, Nicolas Goosen <nicolas@...>
      > wrote:
      > >
      > > Hi,
      > >
      > > (This is my first post, as far as I can remember. Have been a
      > > 'voyeur' on this group for long enough so think it's about time to
      > > step in!)
      > >
      > > Maybe his question leans more towards "what is the highest line-
      > > screen of a PP plate?" - I think, practically, it's about 150 dpi.
      > >
      > > I saw a flexo sample printed by a local label printer a few weeks
      > ago
      > > of a typical press-target type image (bread, flowers, a glass of
      > > wine, etc. still life) - indistinguishable from litho! Apparently
      > off
      > > PP plates. Although I don't know how many out there try halftone
      > work
      > > on their PP plates with regards to letterpress...
      > >
      > > -Nicolas Goosen
      > >
      > > PS Iohannes - you need to get to grips with the difference between
      > > 'resolution of an image-setting/plate-setting device' and the
      > > halftone 'resolution'/dpi that it can thus achieve and please
      > clarify
      > > your question.
      > >
      > >
      > >
      > > On 31 Aug 2008, at 10:00 PM, Gerald Lange wrote:
      > >
      > > > Iohannes
      > > >
      > > > I'm not exactly sure what you are asking as there may be two
      > > > approaches to this.
      > > >
      > > > One would be a measure of the tolarance of a given photopolymer
      > plate.
      > > > Most manufacturers provide this information.
      > > >
      > > > If you are asking what is the resolution required for output, the
      > > > standard is an imagesetter film negative. These are usually
      > generated
      > > > at 2400 dpi (standard), but some machines are capable of up to
      > 5400
      > > > dpi (I usually spec 3600 dpi).
      > > >
      > > > If your concerns are typographic or if you want the finest
      > definition
      > > > and clarity of letterform or imaging, this is your only option.
      > > >
      > > > However, imaging can be generated on laser or ink jet printers at
      > > > resolutions from 600 to 1200 dpi, and there are a couple of laser
      > > > printers capable of emulated 2400 dpi. But you cannot achieve
      > the type
      > > > of quality you would get from imagesetter film, and at $8 to $16
      > for
      > > > an 8.5 x 11 inch film negative, hardly seems worth it to do
      > anything
      > > > less. Besides the lack of refinement in the imaging, there are
      > also
      > > > opacity problems associated with toner-based imaging. A minimum
      > > > density of 3.5 to 4.0 over the opaque areas and a maximum
      > density of
      > > > .05 at transparency are the minimum standard and even the best of
      > > > toner-based film configurations barely reaches this level.
      > > >
      > > > Gerald
      > > > http://BielerPress.blogspot.com
      > > >
      > > > --- In PPLetterpress@yahoogroups.com, "Iohannes Daubmannus"
      > > > <daubmannus@> wrote:
      > > > >
      > > > > Sorry, I'm totally a newbie in the subject of the group
      > > > > and maybe should use search harder, but...
      > > > >
      > > > > What's the resolution can we get with photopolymer plates?
      > > > > It'll be great for me to know average minimum-acceptable,
      > normal and
      > > > > fine values to test my process.
      > > > >
      > > > > Thanks for your opinions.
      > > > >
      > > >
      > > >
      > > >
      > >
      >
      >
      >
    • Iohannes Daubmannus
      Thank you, Nicolas, Gerald. I m asking just about tolarance of a given photopolymer plate . Surely, manufacturers provide this values, but I directly contact
      Message 2 of 15 , Sep 1, 2008
      • 0 Attachment
        Thank you, Nicolas, Gerald.

        I'm asking just about 'tolarance of a given photopolymer plate'.
        Surely, manufacturers provide this values, but I directly contact only
        with resellers, who, by the way, hardly have the slightest idea about
        letterpress printing.

        So, I'm interested in your opinion, what resolution range of a plate
        is normal for letterpress printing. And maybe examples of brands with
        given resolution.

        As of film and imagesetter resolution, I work in the prepress bureau,
        so I have a clear view of resolution and halftone screen frequency
        ('lpi', not 'dpi' by the way) and can use an imagesetter to make a
        film at 2400 or 3600 dpi for example, but I doubt we can get these
        high values on PP.
      • Nicolas Goosen
        Iohannes, Sorry, I stand corrected.
        Message 3 of 15 , Sep 1, 2008
        • 0 Attachment
          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 4 of 15 , Sep 1, 2008
          • 0 Attachment
            > 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 5 of 15 , Sep 1, 2008
            • 0 Attachment
              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 6 of 15 , Sep 1, 2008
              • 0 Attachment
                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 7 of 15 , Sep 1, 2008
                • 0 Attachment
                  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 8 of 15 , Sep 2, 2008
                  • 0 Attachment
                    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 9 of 15 , Sep 2, 2008
                    • 0 Attachment
                      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 10 of 15 , Sep 2, 2008
                      • 0 Attachment
                        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 11 of 15 , Sep 2, 2008
                        • 0 Attachment
                          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.
                          >
                          > ------------------------------------
                          >
                          >
                          >
                        Your message has been successfully submitted and would be delivered to recipients shortly.