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Re: [PPLetterpress] Re: correcting ink spread

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  • Gerald Lange
    ... Mark There are three control parameters for the unsharp mask filter. What are your exact settings for each? Gerald
    Message 1 of 13 , Aug 14, 2002
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      Mark Attwood wrote:
      >
      > Gerald,
      >
      > I find that for some odd reason that unsharp masking at such high levels of
      > 500% seems to open up the areas that are likely to fill in on the press and
      > at the same time strengthen light details that are likely to drop out, as
      > sort of fix-both-problems at the same time solution. I haven't found any
      > other filters that seem to help much though.
      >
      > Mark Attwood
      >
      Mark

      There are three control parameters for the unsharp mask filter. What are your
      exact settings for each?

      Gerald
    • Michael Peich
      ... Hey Gerry, (or should I say, Gerald?) It s been fascinating reading e-mails from this group, although the polymer plate discussions are way over my leaded
      Message 2 of 13 , Aug 14, 2002
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        on 8/14/02 1:13 AM, bielerpr at bieler@... wrote:

        >
        >> Gerald and Erik,
        >>
        >> This may sound a bit too easy, but I have found that unsharp masking
        >> (usually twice at 500%) is the one filter that really seems to open up a
        >> line image for good letterpress printing.
        >>
        >> are there any other filters that you can recommend ?
        >>
        >> thanks,
        >> Mark.
        >>
        >
        > Hi Mark
        >
        > The unsharp mask is quite useful, in some situations, maybe most, but
        > it most usually is one of the last filters you would use in a
        > sequence as it is clearly a "demarcation" filter. The movement is
        > from "fuzz" to clarity. Introduce clarity too soon and you have to
        > retrace your steps.
        >
        > Problem with most of these filters is they really need to be used in
        > combination and seqsuence. Lot of experimentation at first, and every
        > image has its own requirements. More art than science if you are
        > trying to get it right. Can't come up with a consistent recipe.
        >
        > But if unsharp seems to be working, keep doing it. 500% is a huge
        > movement though, isn't it? I'm a bit too cautious perhaps. Maybe I
        > just don't trust in this stuff enough.
        >
        > Gerald
        >
        >
        >
        >
        >
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        >
        >


        Hey Gerry, (or should I say, Gerald?)

        It's been fascinating reading e-mails from this group, although the
        polymer plate discussions are way over my leaded head. You've become the
        guru for this stuff, and impressively knowledgeable.

        One quick piece of business. I am a member of the APHA board of
        directors and at our last meeting I agreed to contact you about your lapsed
        membership. Since you were the individual who encouraged me to join APHA a
        number of years ago, I want to encourage you to renew your membership. Lots
        of good things are happening, and we need all the support we can muster. Do
        it.

        I suspect I'll see you next at Oak Knoll. Have a productive few last
        gasp of summer, and early fall.

        Cheers, Mike
      • Erik Desmyter
        ... 500%, radius about 1.2 pixels and threshold about 5. set the amount at 500 and then play with the radius, at some point you will quickly see you will get
        Message 3 of 13 , Aug 15, 2002
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          > As you say there is a bit more art than science but the usual is: Amount
          500%, radius about 1.2 pixels and threshold about 5. set the amount at 500
          and then play with the radius, at some point you will quickly see you will
          get the optimal result.

          If you go to our PPletterpress website
          http://groups.yahoo.com/group/PPLetterpress/ and go for "Files" (at the left
          side) and then under "How to" you will see 6 small files I have created as
          an example. What I have done is I first made in Adobe photoshop a letter R
          in Times New Roman at 12 points (R created in photoshop 2400ppi.TIF). This
          file was then printed with a standard HP laserprinter 5L at 600dpi and this
          printed document was then scanned at 600ppi, 1200ppi, 2400ppi in line art
          and also 600ppi in grayscales.

          I have also tried the above unsharp masking correction (500%, radius, 1.2
          pixels, 5 threshold) on the grayscale scan (R scan grayscales 600ppi +
          unsharp masking.PDF).

          The goal should be to get back (after the scanning and the clean up) as
          close as possible to the original creation. The printing with a laser
          printer at 600dpi is losing a lot of quality but I think real letterpress
          printing will have more quality loss with more ink spread, etc...

          Please feel free to use one of the 4 scans and try to do some processing or
          correction to get to a good result as close as possible to the original.

          Erik
        • Mark Attwood
          Hi Gerald, As you say there is a bit more art than science but the usual is: Amount 500%, radius about 1.2 pixels and threshold about 5. set the amount at 500
          Message 4 of 13 , Aug 15, 2002
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            Hi Gerald,

            As you say there is a bit more art than science but the usual is: Amount
            500%, radius about 1.2 pixels and threshold about 5. set the amount at 500
            and then play with the radius, at some point you will quickly see you will
            get the optimal result. I don't know if this is the best way, just what I
            have discovered is best for me. I would appreciate any feedback from others
            in this regard.


            Mark Attwood

            The Artists' Press
            Box 623
            Newtown
            2113
            South Africa

            Tel. +27 11 836 5474
            fax. +27 11 836 6858
            mark@...


            ----------
            >From: Gerald Lange <bieler@...>
            >To: PPLetterpress@yahoogroups.com
            >Subject: Re: [PPLetterpress] Re: correcting ink spread
            >Date: Wed, Aug 14, 2002, 9:30 am
            >

            > Mark Attwood wrote:
            >>
            >> Gerald,
            >>
            >> I find that for some odd reason that unsharp masking at such high levels of
            >> 500% seems to open up the areas that are likely to fill in on the press and
            >> at the same time strengthen light details that are likely to drop out, as
            >> sort of fix-both-problems at the same time solution. I haven't found any
            >> other filters that seem to help much though.
            >>
            >> Mark Attwood
            >>
            > Mark
            >
            > There are three control parameters for the unsharp mask filter. What are your
            > exact settings for each?
            >
            > Gerald
            >
            >
            >
            > ï To respond to a post or post a message to the membership:
            > PPLetterpress@yahoogroups.com
            > ï Encountering problems? contact:
            > PPLetterpress-owner@yahoogroups.com
            > ï To unsubscribe:
            > PPLetterpress-unsubscribe@yahoogroups.com
            >
            > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
            >
          • Gerald Lange
            Hi Gerald, As you say there is a bit more art than science but the usual is: Amount 500%, radius about 1.2 pixels and threshold about 5. set the amount at 500
            Message 5 of 13 , Aug 15, 2002
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              Hi Gerald,

              As you say there is a bit more art than science
              but the usual is: Amount
              500%, radius about 1.2 pixels and threshold about
              5. set the amount at 500
              and then play with the radius, at some point you
              will quickly see you will
              get the optimal result. I don't know if this is
              the best way, just what I
              have discovered is best for me. I would
              appreciate any feedback from others
              in this regard.


              Mark Attwood

              The Artists' Press
              Box 623
              Newtown
              2113
              South Africa

              Tel. +27 11 836 5474
              fax. +27 11 836 6858
              mark@...

              Dear Mark

              Thought I'd test this out with a something I would have found quite difficult.
              I downloaded an image of one of Tycho's Brahe's astronomical instruments,
              printed in the 16th century. This was a very colorful JPEG at 300 dpi. I
              opened it in Photoshop, re-sampled to 600 dpi and converted it to a grayscale.
              I ran your formula twice and converted the file to b/w bitmap while
              re-sampling to 1200 dpi. I printed it out at 1200 dpi. Fell out of my chair.
              Absolute clarity and as perfect a conversion of the blacks and whites as I
              have ever seen. All in about five minutes of time!!!

              You have found the Holy Grail my son. I get down on my knees to you.

              All best

              Gerald
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