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Re: [PPLetterpress] Re: PPWeirdness (dampening follow up)

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  • Gerald Lange
    Hi Bryan My thinking is that commercial grade papers tend not to respond well to dampening. Primarily because of dominant grain direction and external sizing.
    Message 1 of 23 , May 9, 2008
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      Hi Bryan

      My thinking is that commercial grade papers tend not to respond well to
      dampening. Primarily because of dominant grain direction and external
      sizing.

      I think the only commercial grade that I dampen is Curtis Flannel but my
      suspicion, is that it might actually have been a mouldmade, coming from
      the Scottish mills that Curtis owned. We had it tested once and the
      report came back that it consisted of tobacco leaves. I believe it was
      engine sized. Great printing paper no longer with us.

      One of my students had some double ply Lettra last semester. A very
      thick sheet that she was attempting to print on the Vandercook. Not only
      did the layers split apart but the entire back ply was warped throughout
      the heap. Might have been a bad lot or badly stored. Not a big fan.

      I don't know that you need to dampen on thinner stock. Most of the text
      weight mouldmades print well without dampening, though they do respond
      well when dampened. I guess I'd suggest dampening only when you really
      need to do it.

      An aside, but it does relate to the old thread you encountered. I
      believe some was asking about the bulging between letters that they were
      experiencing when printing on Cranes Lettra with the "deep relief"
      plate. I occurred to me the other day that the problem arises from
      relief depth. Subtract the relief thickness of a plate from the plate
      thickness and you get its relief depth. A Toyobo 95 mm K series plate
      has a 65 mm relief thickness. A Toyobo 1.52 mm K series plate has a 1.22
      mm relief thickness. Thus, surprise, surprise, they both have a relief
      depth of .30 mm. While the 152 is deeper (thicker) from surface to
      floor, material in close proximity at the surface (small text,
      letterform counters, etc) however, is limited to the relief depth.
      That's just the way the formation process works. Any other ratio in
      regard to relief depth would make the plate unstable. Thus you will get
      the bulging effect when you over impress as you are extending beyond the
      capability of the plate. The paper has to do something under the forced
      pressure so it bulges out where it can or even cracks. This would also
      account for the loss of isolated dots, fine lines, etc, on these plates
      under severe impression as they simply have no support.

      Gerald
      http://BielerPress.blogspot.com

      kringds wrote:
      > Hi Gerald,
      >
      > I was browsing the archives on dampening paper and came across your post below in
      > which you seem suprised at the dampening of Lettra. Could you tell me why you were
      > supprised?
      >
      > I am getting ready to print a job on 32# lettra and am debating if I should dampen the
      > paper. I will be printing on polymer plates with primarily line art with black ink.
      >
      > I have dampened heavier weight paper before with good results but I am wondering if it
      > makes sense for a lighter weight paper. I assume it does. Could you or anyone with
      > experience let me know their opinion on this?
      >
      > As always, thanks for the help and advice.
      >
      > bryan kring
      >
      >
      >
      > --- In PPLetterpress@yahoogroups.com, "Gerald Lange" <Bieler@...> wrote:
      >
      >> Probably. I still have demon catchers hanging from the ceiling, though
      >> I have taken down all the tribute images of Moloch.
      >>
      >> Dampened Lettra!!! Interesting.
      >>
      >> Gerald
      >> http://BielerPress.blogspot.com
      >>
      >>
      >>
      >>> Yes. As noted I've had plenty of good luck before Mercury retrograde
      >>>
      >> started ;-)
      >>
      >>> These little 'antelope' greeting cards were done with the 'old'
      >>>
      >> yellow pp... ( dampened Lettra on the V219)
      >>
      >> http://www.exquisiteletterpress.com/cards/exquisitegreetingcards/archive/samples/
      >>
      > unique-invitation-designs-by-kf/P1020933.JPG
      >
      >>> Maybe it's the wrong Moon sign for platemaking?
      >>>
      >>> Ciao
      >>> p
      >>>
      >>>
      >>>
      >>>
      >
    • Peter Fraterdeus
      Bryan, Gerald, Dampening worked well on the 300gsm Lettra Assuming one is doing single color work, variation in grain doesn t really come into it. Also, even
      Message 2 of 23 , May 9, 2008
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        Bryan, Gerald,

        Dampening worked well on the 300gsm Lettra
        Assuming one is doing single color work, variation in grain doesn't
        really come into it.
        Also, even with multiple colors, keeping the stock lightly wrapped
        between impressions will minimize dimensional variation.

        Double ply, 600gsm, I can imagine may be a problem on the cylinder,
        yes...

        As far as the other concern that Gerald alludes to, the plate in
        question was neither of the Toyobos, but a leftover that was acquired
        previously. I've had none of these problems with the Toyobo 152. One
        thing is that I've found that keeping the washout to the absolute
        minimum is critical, and often pull the plate while there are still
        small amounts of material adhering to the backing. (about 4.5 minutes)
        With this, I get lovely shoulders on even isolated thin rules and
        dots...

        My concern had nothing to do with "bulging" between the letters, but
        the fact that there was so little definition between the letters, so
        that the whole line of type appeared to be surrounded by a slight
        depression caused by very shallow shoulders. With the Toyobo (either
        95 or 152) I've not had this problem. While the impression was not
        wimpy, neither was it excessive. There is never embossing on the verso.

        Cheers
        P


        On 8 May 2008, at 6:43 PM, kringds wrote:
        > Hi Gerald,
        >
        > I was browsing the archives on dampening paper and came across your
        > post below in
        > which you seem suprised at the dampening of Lettra. Could you tell
        > me why you were
        > supprised?
        >
        > I am getting ready to print a job on 32# lettra and am debating if I
        > should dampen the
        > paper. I will be printing on polymer plates with primarily line art
        > with black ink.
        >
        > I have dampened heavier weight paper before with good results but I
        > am wondering if it
        > makes sense for a lighter weight paper. I assume it does. Could you
        > or anyone with
        > experience let me know their opinion on this?
        >
        > As always, thanks for the help and advice.
        >
        > bryan kring

        Peter Fraterdeus
        Exquisite Letterpress
        http://slowprint.com
      • Gerald Lange
        Peter Don t know that the other concern was in reference to you, but you might even want to back down to 4 minutes on washout for the Toyobo 152s. It ll leave
        Message 3 of 23 , May 9, 2008
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          Peter

          Don't know that the other concern was in reference to you, but you
          might even want to back down to 4 minutes on washout for the Toyobo
          152s. It 'll leave a bit of residue and not look as nice as one might
          hope, but it will definitely prevent undercutting and ensure support.
          These are steel-backs. Don't know about the polyester-backed 152s.

          The Toybobo 95s are a dream plate. Perfectly clean at 3.5 minute
          washout, no residue, no undercutting, steel- or polyester-backed.

          Gerald
          http://BielerPress.blogspot.com

          --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...> wrote:
          >
          > Bryan, Gerald,
          >
          > Dampening worked well on the 300gsm Lettra
          > Assuming one is doing single color work, variation in grain doesn't
          > really come into it.
          > Also, even with multiple colors, keeping the stock lightly wrapped
          > between impressions will minimize dimensional variation.
          >
          > Double ply, 600gsm, I can imagine may be a problem on the cylinder,
          > yes...
          >
          > As far as the other concern that Gerald alludes to, the plate in
          > question was neither of the Toyobos, but a leftover that was acquired
          > previously. I've had none of these problems with the Toyobo 152. One
          > thing is that I've found that keeping the washout to the absolute
          > minimum is critical, and often pull the plate while there are still
          > small amounts of material adhering to the backing. (about 4.5 minutes)
          > With this, I get lovely shoulders on even isolated thin rules and
          > dots...
          >
          > My concern had nothing to do with "bulging" between the letters, but
          > the fact that there was so little definition between the letters, so
          > that the whole line of type appeared to be surrounded by a slight
          > depression caused by very shallow shoulders. With the Toyobo (either
          > 95 or 152) I've not had this problem. While the impression was not
          > wimpy, neither was it excessive. There is never embossing on the verso.
          >
          > Cheers
          > P
          >
          >
          > On 8 May 2008, at 6:43 PM, kringds wrote:
          > > Hi Gerald,
          > >
          > > I was browsing the archives on dampening paper and came across your
          > > post below in
          > > which you seem suprised at the dampening of Lettra. Could you tell
          > > me why you were
          > > supprised?
          > >
          > > I am getting ready to print a job on 32# lettra and am debating if I
          > > should dampen the
          > > paper. I will be printing on polymer plates with primarily line art
          > > with black ink.
          > >
          > > I have dampened heavier weight paper before with good results but I
          > > am wondering if it
          > > makes sense for a lighter weight paper. I assume it does. Could you
          > > or anyone with
          > > experience let me know their opinion on this?
          > >
          > > As always, thanks for the help and advice.
          > >
          > > bryan kring
          >
          > Peter Fraterdeus
          > Exquisite Letterpress
          > http://slowprint.com
          >
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