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[PPLetterpress] Re: PP beard...

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  • Peter Fraterdeus
    Thanks, Gerald, et alia This is pretty much what I suspected, but thought I d ask anyway, just for the record As I said, I ve had very nice results from mag
    Message 1 of 21 , Dec 25, 2007
      Thanks, Gerald, et alia

      This is pretty much what I suspected, but thought I'd ask anyway, just for the record

      As I said, I've had very nice results from mag plates, haven't looked into copper, sounds expensive!

      Best wishes
      P.

      At 6:30 PM +0000 25 12 07, Gerald Lange wrote:
      >Hi Peter
      >
      >I think you are going to find that with a very deep impression on a
      >cushionable paper like Lettra, that this is the look you are going to
      >get. You might try a nylon based plate (Toyobo Printight or BASF
      >nyloprint) but it won't help that much. There is no magic
      >exposure/washout formula that will resolve this. It is the built in
      >limitation to the photopolymer plate process; it's not meant for this
      >(unless, of course, you just ignore or are unaware of the problem).
      >
      >Your perfect alternative (beard-wise) are copper photoengravings
      >(generated from imagesetter film) mounted either on a patent or
      >honeycomb base or a magnesium flatbase. That, or look for a different
      >impression/paper that provides you the look that you expect from type.
      >
      >Gerald
      >http://BielerPress.blogspot.com

      --
      AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
      ExquisiteLetterpress http://www.exquisiteletterpress.com

      -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*
      Peter Fraterdeus http://www.alphabets.com : Sign up for "MiceType"!
      Galena, Illinois Design Philosophy Fonts Lettering Letterpress Wood Type
      Dubuque, Iowa http://www.fraterdeus.com
      Photography Irish Fiddle Political Observation
      http://flickr.com/photos/pfraterdeus
      http://youtube.com/user/pfraterdeus
    • Lance Williams
      Peter, Actually, from Owosso in Michigan, copper plates are only slightly more expensive than magnesium plates, and they last much longer and give much
      Message 2 of 21 , Dec 25, 2007
        Peter,

        Actually, from Owosso in Michigan, copper plates are only slightly more
        expensive than magnesium plates, and they last much longer and give much
        sharper details.... I have used Owosso for several years now, and they are
        great on customer relations and service...

        Merry Christmas

        - Lance Williams
        Williams Stationery Co
        Camden, New York


        > [Original Message]
        > From: Peter Fraterdeus <peterf@...>
        > To: <PPLetterpress@yahoogroups.com>
        > Date: 12/25/2007 2:24:20 PM
        > Subject: [PPLetterpress] Re: PP beard...
        >
        > Thanks, Gerald, et alia
        >
        > This is pretty much what I suspected, but thought I'd ask anyway, just
        for the record
        >
        > As I said, I've had very nice results from mag plates, haven't looked
        into copper, sounds expensive!
        >
        > Best wishes
        > P.
        >
        > At 6:30 PM +0000 25 12 07, Gerald Lange wrote:
        > >Hi Peter
        > >
        > >I think you are going to find that with a very deep impression on a
        > >cushionable paper like Lettra, that this is the look you are going to
        > >get. You might try a nylon based plate (Toyobo Printight or BASF
        > >nyloprint) but it won't help that much. There is no magic
        > >exposure/washout formula that will resolve this. It is the built in
        > >limitation to the photopolymer plate process; it's not meant for this
        > >(unless, of course, you just ignore or are unaware of the problem).
        > >
        > >Your perfect alternative (beard-wise) are copper photoengravings
        > >(generated from imagesetter film) mounted either on a patent or
        > >honeycomb base or a magnesium flatbase. That, or look for a different
        > >impression/paper that provides you the look that you expect from type.
        > >
        > >Gerald
        > >http://BielerPress.blogspot.com
        >
        > --
        > AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
        > ExquisiteLetterpress http://www.exquisiteletterpress.com
        >
        >
        -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*
        -:-*-:-*-:-*-:-*
        > Peter Fraterdeus http://www.alphabets.com : Sign up for "MiceType"!
        > Galena, Illinois Design Philosophy Fonts Lettering Letterpress Wood Type
        > Dubuque, Iowa http://www.fraterdeus.com
        > Photography Irish Fiddle Political Observation
        > http://flickr.com/photos/pfraterdeus
        > http://youtube.com/user/pfraterdeus
        >
        >
        >
        >
        >
        > Yahoo! Groups Links
        >
        >
        >
      • Gerald Lange
        Hi again Yes, quite expensive, but only relatively so. Depends upon what you are looking for in print quality and what you are printing. Copper would bankrupt
        Message 3 of 21 , Dec 25, 2007
          Hi again

          Yes, quite expensive, but only relatively so. Depends upon what you are
          looking for in print quality and what you are printing. Copper would
          bankrupt you if you were a book printer, but then so would foundry type.
          But for card work it certainly seems the ticket. For embossing, foil
          stamping, it is simply the best surface/structure around. Best
          materials, best tools, best equipment, etc., help to ensure better
          quality. Time tested formula.

          Had photoengravers caught on to imagesetter film negatives far earlier
          than they did, I suspect photopolymer would not have been able to make
          quite the inroads that it did. The real success of photopolymer is not
          the process itself, it has been around since the early 1960s, but rather
          its immediate conjunction with digital imaging technology.
          Photoengravers ignored that for years (mainly, I'd guess, because they
          had substantial investment in analog photo technology and it did not
          seem feasible to switch over).

          Gerald
          http://BielerPress.blogspot.com

          Peter Fraterdeus wrote:
          > Thanks, Gerald, et alia
          >
          > This is pretty much what I suspected, but thought I'd ask anyway, just for the record
          >
          > As I said, I've had very nice results from mag plates, haven't looked into copper, sounds expensive!
          >
          > Best wishes
          > P.
          >
          > At 6:30 PM +0000 25 12 07, Gerald Lange wrote:
          >
          >> Hi Peter
          >>
          >> I think you are going to find that with a very deep impression on a
          >> cushionable paper like Lettra, that this is the look you are going to
          >> get. You might try a nylon based plate (Toyobo Printight or BASF
          >> nyloprint) but it won't help that much. There is no magic
          >> exposure/washout formula that will resolve this. It is the built in
          >> limitation to the photopolymer plate process; it's not meant for this
          >> (unless, of course, you just ignore or are unaware of the problem).
          >>
          >> Your perfect alternative (beard-wise) are copper photoengravings
          >> (generated from imagesetter film) mounted either on a patent or
          >> honeycomb base or a magnesium flatbase. That, or look for a different
          >> impression/paper that provides you the look that you expect from type.
          >>
          >> Gerald
          >> http://BielerPress.blogspot.com
          >>
          >
          >
        • nagraph@ekiva.net
          And magnesium and copper plates don t have to be the more expensive 1/4 plates normally used for embossing, foil, or use with patent bases. Unmounted mag and
          Message 4 of 21 , Dec 25, 2007
            And magnesium and copper plates don't have to be the more expensive 1/4"
            plates normally used for embossing, foil, or use with patent bases.
            Unmounted mag and copper of the 16 gauge variety, same as used for wood
            mounted engravings can work just as well with a suitable base and an
            adhesive mounting system. The plates are less expensive because of lower
            material costs. Copper has scrap value and once a plate is dead because of
            dates or the event is over, then it goes into a 5 gallon bucket to be sold
            at some point to a scrap dealer. I know one printer who pays for a very
            nice employee Christmas party each year from the copper sales.

            Most photoengravers accept electronic files and still produce film
            negatives and can produce the required magnesium engravings, and ones like
            Owosso and Metal Magic do copper as well. Multiple image plates can be cut
            apart in metal just as in photoploymer.

            Magnesium has a downside because of its flammability, especially when
            trimmed on a saw. The shavings and bits of metal can ignite into a
            fearsome fire, if enough is present, and have to be treated with great
            care. I was told of a recent fire in a print shop fron magnesium cuttings
            in a Hammond Glider saw when the blade was being used to cut some wood
            that had an undetected brad in it, and a resulting spark ignited a couple
            of inches of magnesium in the scrap bin--flames 5 feet high erupted with
            an intense heat and only quick action of pulling the container outside
            prevented a major fire. The stuff deserves its due respect.

            Fritz

            > Thanks, Gerald, et alia
            >
            > This is pretty much what I suspected, but thought I'd ask anyway, just for
            > the record
            >
            > As I said, I've had very nice results from mag plates, haven't looked into
            > copper, sounds expensive!
            >
            > Best wishes
            > P.
            >
            > At 6:30 PM +0000 25 12 07, Gerald Lange wrote:
            >>Hi Peter
            >>
            >>I think you are going to find that with a very deep impression on a
            >>cushionable paper like Lettra, that this is the look you are going to
            >>get. You might try a nylon based plate (Toyobo Printight or BASF
            >>nyloprint) but it won't help that much. There is no magic
            >>exposure/washout formula that will resolve this. It is the built in
            >>limitation to the photopolymer plate process; it's not meant for this
            >>(unless, of course, you just ignore or are unaware of the problem).
            >>
            >>Your perfect alternative (beard-wise) are copper photoengravings
            >>(generated from imagesetter film) mounted either on a patent or
            >>honeycomb base or a magnesium flatbase. That, or look for a different
            >>impression/paper that provides you the look that you expect from type.
            >>
            >>Gerald
            >>http://BielerPress.blogspot.com
            >
          • John G. Henry
            The only way to get substantially steeper shoulders in photopolymer platemaking is to use a less diffuse lightsource. When first using photopolymer plates, I
            Message 5 of 21 , Dec 26, 2007
              The only way to get substantially steeper shoulders in photopolymer
              platemaking is to use a less diffuse lightsource. When first using
              photopolymer plates, I exposed the plates using pretty standard
              exposure frame designed for magnesium and copper plate exposures,
              using a 5 KW plate exposure lamp. In order to get any angle to the
              shoulder (the slope on the edge of the image line) I had to use a
              frosted diffusing film on top of the negative, otherwise the
              shoulders were almost straight vertical. When producing photopolymer
              pattern plates for brass engraving, the steep shoulder was what we
              desired, but for printing purposes I needed support of the image.

              The polymer exposure units have been intentionally designed with
              diffuse fluorescent lighting, to produce that angled shoulder, thus
              giving better support to fine lines and halftone dots, which
              otherwise would not take the pressure of printing.

              In Dow Powderless Etching process for metal plates, the shoulder can
              be adjusted by changing the speed of the paddles which flip the
              acid/oil mixture up to the surface of the plate. The faster the
              paddle speed, the steeper the shoulders produced. The shoulder angle
              is also effected by the strength of the acid/water/oil mixture in
              the bath.

              --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...>
              wrote:
              >
              > Since the snow white bushy beard is seen about this time of year,
              I'll posit my concern about photopolymer 'beards', wondering if
              there's any technique whereby one can gain a more vertical bite from
              photopolymer, more akin to type? As it is, I'm getting a nice depth
              of impression and a very clean, sharp imprint. For 'cuts' (ie,
              images) that's all that's required.
              >
              > However with type, the impression, sharp and crisp as a pink lady
              apple on an October afternoon, sits at the bottom of a conical well,
              each letter in its own little crater*. With real type or acid-etched
              (mag/zinc) plate one doesn't see these craters blending from one
              letter to the next.
              >
              > * Note that this is on 300 gsm Crane's Lettra. There is no punch-
              through on the verso.
              >
              > I assume this is due to the spread of the UV into the pp matrix,
              which of course is necessary for the strength to hold up fine
              details etc to the pressure of printing.
              >
              > My thinking is that it's probably just an inevitable, if
              unfortunate, result of the way these plates handle exposure and the
              water washout. The magnesium plates I get have a very crisp beard,
              much closer to that of real type. I expect that the acid etching of
              an opaque metal allows this.
              >
              > I wonder if there's any way to minimize the angle of the
              cone/beard, while maintaining the depth of 'etch' on these plates?
              I'm currently using Jet plastic-backed plates and the Interflex A4
              platemaker.
              > Typical exposure about 3.5 minutes, washout about 5.5 min.
              >
              > The only way I can think to minimize this concern would be to move
              the lights further from the plate during exposure (ie more of a
              point light) But this is not an option in the A4 Interflex...
              >
              > Hmmm
              >
              > Merry Christmas to all, Happy Solstice Season!
              > Best wishes for 2008!
              >
              > Peter
              >
              >
              > --
              > AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
              > {ARTQ: Help stop in-box bloat! Always Remember to Trim the Quote!}
              >
              > ExquisiteLetterpress http://www.exquisiteletterpress.com
              >
              > -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-
              *-:-*-:-*-:-*-:-*-:-*-:-*
              > Peter Fraterdeus http://www.alphabets.com : Sign up
              for "MiceType"!
              > Galena, Illinois Design Philosophy Fonts Lettering
              Letterpress Wood Type
              > Dubuque, Iowa http://www.fraterdeus.com
              > Photography Irish Fiddle Political Observation
              > http://flickr.com/photos/pfraterdeus
              > http://youtube.com/user/pfraterdeus
              >
            • Lisa Davidson
              Hi, John, Peter, etc. I totally don t get this, because I mean from a physical standpoint you would think that a point source would give a vertical shoulder,
              Message 6 of 21 , Dec 26, 2007
                Hi, John, Peter, etc.

                I totally don't get this, because I mean from a physical standpoint
                you would think that a point source would give a vertical shoulder,
                and a diffuse light source would give an undercut. I mean, the light
                is coming in from all different directions, and if something is side-
                lighted it ought to be exposed further under. I realize the facts
                are all saying the opposite, but why on earth would that be?

                Thank you,

                Lisa


                On Dec 26, 2007, at 8:43 AM, John G. Henry wrote:

                > The only way to get substantially steeper shoulders in photopolymer
                > platemaking is to use a less diffuse lightsource. When first using
                > photopolymer plates, I exposed the plates using pretty standard
                > exposure frame designed for magnesium and copper plate exposures,
                > using a 5 KW plate exposure lamp. In order to get any angle to the
                > shoulder (the slope on the edge of the image line) I had to use a
                > frosted diffusing film on top of the negative, otherwise the
                > shoulders were almost straight vertical. When producing photopolymer
                > pattern plates for brass engraving, the steep shoulder was what we
                > desired, but for printing purposes I needed support of the image.
                >
                > The polymer exposure units have been intentionally designed with
                > diffuse fluorescent lighting, to produce that angled shoulder, thus
                > giving better support to fine lines and halftone dots, which
                > otherwise would not take the pressure of printing.
                >
                > In Dow Powderless Etching process for metal plates, the shoulder can
                > be adjusted by changing the speed of the paddles which flip the
                > acid/oil mixture up to the surface of the plate. The faster the
                > paddle speed, the steeper the shoulders produced. The shoulder angle
                > is also effected by the strength of the acid/water/oil mixture in
                > the bath.
                >
                > --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...>
                > wrote:
                > >
                > > Since the snow white bushy beard is seen about this time of year,
                > I'll posit my concern about photopolymer 'beards', wondering if
                > there's any technique whereby one can gain a more vertical bite from
                > photopolymer, more akin to type? As it is, I'm getting a nice depth
                > of impression and a very clean, sharp imprint. For 'cuts' (ie,
                > images) that's all that's required.
                > >
                > > However with type, the impression, sharp and crisp as a pink lady
                > apple on an October afternoon, sits at the bottom of a conical well,
                > each letter in its own little crater*. With real type or acid-etched
                > (mag/zinc) plate one doesn't see these craters blending from one
                > letter to the next.
                > >
                > > * Note that this is on 300 gsm Crane's Lettra. There is no punch-
                > through on the verso.
                > >
                > > I assume this is due to the spread of the UV into the pp matrix,
                > which of course is necessary for the strength to hold up fine
                > details etc to the pressure of printing.
                > >
                > > My thinking is that it's probably just an inevitable, if
                > unfortunate, result of the way these plates handle exposure and the
                > water washout. The magnesium plates I get have a very crisp beard,
                > much closer to that of real type. I expect that the acid etching of
                > an opaque metal allows this.
                > >
                > > I wonder if there's any way to minimize the angle of the
                > cone/beard, while maintaining the depth of 'etch' on these plates?
                > I'm currently using Jet plastic-backed plates and the Interflex A4
                > platemaker.
                > > Typical exposure about 3.5 minutes, washout about 5.5 min.
                > >
                > > The only way I can think to minimize this concern would be to move
                > the lights further from the plate during exposure (ie more of a
                > point light) But this is not an option in the A4 Interflex...
                > >
                > > Hmmm
                > >
                > > Merry Christmas to all, Happy Solstice Season!
                > > Best wishes for 2008!
                > >
                > > Peter
                > >
                > >
                > > --
                > > AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
                > > {ARTQ: Help stop in-box bloat! Always Remember to Trim the Quote!}
                > >
                > > ExquisiteLetterpresshttp://www.exquisiteletterpress.com
                > >
                > > -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-
                > *-:-*-:-*-:-*-:-*-:-*-:-*
                > > Peter Fraterdeus http://www.alphabets.com : Sign up
                > for "MiceType"!
                > > Galena, Illinois Design Philosophy Fonts Lettering
                > Letterpress Wood Type
                > > Dubuque, Iowa http://www.fraterdeus.com
                > > Photography Irish Fiddle Political Observation
                > > http://flickr.com/photos/pfraterdeus
                > > http://youtube.com/user/pfraterdeus
                > >
                >
                >
                >



                [Non-text portions of this message have been removed]
              • Gerald Lange
                Lisa If I understand your question correctly you might want to envision the process as if it were a sand dial. As the UV light passes through the transparency
                Message 7 of 21 , Dec 26, 2007
                  Lisa

                  If I understand your question correctly you might want to envision the
                  process as if it were a sand dial.

                  As the UV light passes through the transparency of the film negative it
                  spreads out, forming the sloping relief. The slope remains the same but
                  the longer the exposure the less relief you will have as it is growing
                  upward as well.

                  UV light effects the photopolymer by altering its molecular structure.
                  The molecules grow longer and become more complex. They are becoming
                  insoluble. The bridging problem is caused by near proximity of surface
                  elements. The relief is higher in these areas. In some cases, especially
                  with deep relief printing, this subsurface relief, while it may not
                  print, will actually show as a slight indent to the paper.

                  Often a problem with digital type, regardless of impression, is the
                  close fitting of certain characters, especially at small sizes. The
                  relief builds up, providing support, but also increasing the possibility
                  of bridging. A solution to this is alteration of the character fitting
                  at the prepress stage. This problem will also occur in complex fine line
                  work in images as well as halftones.

                  The photopolymer plate process does have its inherent limitations. The
                  finest work is going to be achieved by paying attention to this and
                  working within the latitude of possibility rather than forcing beyond.

                  Gerald

                  Lisa Davidson wrote:
                  > Hi, John, Peter, etc.
                  >
                  > I totally don't get this, because I mean from a physical standpoint
                  > you would think that a point source would give a vertical shoulder,
                  > and a diffuse light source would give an undercut. I mean, the light
                  > is coming in from all different directions, and if something is side-
                  > lighted it ought to be exposed further under. I realize the facts
                  > are all saying the opposite, but why on earth would that be?
                  >
                  > Thank you,
                  >
                  > Lisa
                  >
                  >
                  > On Dec 26, 2007, at 8:43 AM, John G. Henry wrote:
                  >
                  >
                  >> The only way to get substantially steeper shoulders in photopolymer
                  >> platemaking is to use a less diffuse lightsource. When first using
                  >> photopolymer plates, I exposed the plates using pretty standard
                  >> exposure frame designed for magnesium and copper plate exposures,
                  >> using a 5 KW plate exposure lamp. In order to get any angle to the
                  >> shoulder (the slope on the edge of the image line) I had to use a
                  >> frosted diffusing film on top of the negative, otherwise the
                  >> shoulders were almost straight vertical. When producing photopolymer
                  >> pattern plates for brass engraving, the steep shoulder was what we
                  >> desired, but for printing purposes I needed support of the image.
                  >>
                  >> The polymer exposure units have been intentionally designed with
                  >> diffuse fluorescent lighting, to produce that angled shoulder, thus
                  >> giving better support to fine lines and halftone dots, which
                  >> otherwise would not take the pressure of printing.
                  >>
                  >> In Dow Powderless Etching process for metal plates, the shoulder can
                  >> be adjusted by changing the speed of the paddles which flip the
                  >> acid/oil mixture up to the surface of the plate. The faster the
                  >> paddle speed, the steeper the shoulders produced. The shoulder angle
                  >> is also effected by the strength of the acid/water/oil mixture in
                  >> the bath.
                  >>
                  >> --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...>
                  >> wrote:
                  >>
                  >>> Since the snow white bushy beard is seen about this time of year,
                  >>>
                  >> I'll posit my concern about photopolymer 'beards', wondering if
                  >> there's any technique whereby one can gain a more vertical bite from
                  >> photopolymer, more akin to type? As it is, I'm getting a nice depth
                  >> of impression and a very clean, sharp imprint. For 'cuts' (ie,
                  >> images) that's all that's required.
                  >>
                  >>> However with type, the impression, sharp and crisp as a pink lady
                  >>>
                  >> apple on an October afternoon, sits at the bottom of a conical well,
                  >> each letter in its own little crater*. With real type or acid-etched
                  >> (mag/zinc) plate one doesn't see these craters blending from one
                  >> letter to the next.
                  >>
                  >>> * Note that this is on 300 gsm Crane's Lettra. There is no punch-
                  >>>
                  >> through on the verso.
                  >>
                  >>> I assume this is due to the spread of the UV into the pp matrix,
                  >>>
                  >> which of course is necessary for the strength to hold up fine
                  >> details etc to the pressure of printing.
                  >>
                  >>> My thinking is that it's probably just an inevitable, if
                  >>>
                  >> unfortunate, result of the way these plates handle exposure and the
                  >> water washout. The magnesium plates I get have a very crisp beard,
                  >> much closer to that of real type. I expect that the acid etching of
                  >> an opaque metal allows this.
                  >>
                  >>> I wonder if there's any way to minimize the angle of the
                  >>>
                  >> cone/beard, while maintaining the depth of 'etch' on these plates?
                  >> I'm currently using Jet plastic-backed plates and the Interflex A4
                  >> platemaker.
                  >>
                  >>> Typical exposure about 3.5 minutes, washout about 5.5 min.
                  >>>
                  >>> The only way I can think to minimize this concern would be to move
                  >>>
                  >> the lights further from the plate during exposure (ie more of a
                  >> point light) But this is not an option in the A4 Interflex...
                  >>
                  >>> Hmmm
                  >>>
                  >>> Merry Christmas to all, Happy Solstice Season!
                  >>> Best wishes for 2008!
                  >>>
                  >>> Peter
                  >>>
                  >>>
                  >>> --
                  >>> AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
                  >>> {ARTQ: Help stop in-box bloat! Always Remember to Trim the Quote!}
                  >>>
                  >>> ExquisiteLetterpresshttp://www.exquisiteletterpress.com
                  >>>
                  >>> -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-
                  >>>
                  >> *-:-*-:-*-:-*-:-*-:-*-:-*
                  >>
                  >>> Peter Fraterdeus http://www.alphabets.com : Sign up
                  >>>
                  >> for "MiceType"!
                  >>
                  >>> Galena, Illinois Design Philosophy Fonts Lettering
                  >>>
                  >> Letterpress Wood Type
                  >>
                  >>> Dubuque, Iowa http://www.fraterdeus.com
                  >>> Photography Irish Fiddle Political Observation
                  >>> http://flickr.com/photos/pfraterdeus
                  >>> http://youtube.com/user/pfraterdeus
                  >>>
                  >>>
                  >>
                  >>
                  >
                  >
                • Scott Rubel
                  This is a good explanation and helps with the understanding a lot. Thanks, Gerald. I had always assumed that the slope was caused by the amount of time the
                  Message 8 of 21 , Dec 26, 2007
                    This is a good explanation and helps with the understanding a lot.
                    Thanks, Gerald.

                    I had always assumed that the slope was caused by the amount of time
                    the water spends eating away at each level of depth from surface to
                    steel back. I'm good at making up my own science that way.

                    Scott Rubel


                    On Dec 26, 2007, at 11:00 AM, Gerald Lange wrote:

                    > Lisa
                    >
                    > If I understand your question correctly you might want to envision the
                    > process as if it were a sand dial.
                    >
                    > As the UV light passes through the transparency of the film
                    > negative it
                    > spreads out, forming the sloping relief. The slope remains the same
                    > but
                    > the longer the exposure the less relief you will have as it is growing
                    > upward as well.
                    >
                    > UV light effects the photopolymer by altering its molecular structure.
                    > The molecules grow longer and become more complex. They are becoming
                    > insoluble. The bridging problem is caused by near proximity of surface
                    > elements. The relief is higher in these areas. In some cases,
                    > especially
                    > with deep relief printing, this subsurface relief, while it may not
                    > print, will actually show as a slight indent to the paper.
                    >
                    > Often a problem with digital type, regardless of impression, is the
                    > close fitting of certain characters, especially at small sizes. The
                    > relief builds up, providing support, but also increasing the
                    > possibility
                    > of bridging. A solution to this is alteration of the character fitting
                    > at the prepress stage. This problem will also occur in complex fine
                    > line
                    > work in images as well as halftones.
                    >
                    > The photopolymer plate process does have its inherent limitations. The
                    > finest work is going to be achieved by paying attention to this and
                    > working within the latitude of possibility rather than forcing beyond.
                    >
                    > Gerald
                    >
                    > Lisa Davidson wrote:
                    >> Hi, John, Peter, etc.
                    >>
                    >> I totally don't get this, because I mean from a physical standpoint
                    >> you would think that a point source would give a vertical shoulder,
                    >> and a diffuse light source would give an undercut. I mean, the light
                    >> is coming in from all different directions, and if something is side-
                    >> lighted it ought to be exposed further under. I realize the facts
                    >> are all saying the opposite, but why on earth would that be?
                    >>
                    >> Thank you,
                    >>
                    >> Lisa


                    [Non-text portions of this message have been removed]
                  • Lisa Davidson
                    OK, thanks! Lisa ... [Non-text portions of this message have been removed]
                    Message 9 of 21 , Dec 26, 2007
                      OK, thanks!

                      Lisa


                      On Dec 26, 2007, at 11:00 AM, Gerald Lange wrote:

                      > Lisa
                      >
                      > If I understand your question correctly you might want to envision the
                      > process as if it were a sand dial.
                      >
                      > As the UV light passes through the transparency of the film
                      > negative it
                      > spreads out, forming the sloping relief. The slope remains the same
                      > but
                      > the longer the exposure the less relief you will have as it is growing
                      > upward as well.
                      >
                      > UV light effects the photopolymer by altering its molecular structure.
                      > The molecules grow longer and become more complex. They are becoming
                      > insoluble. The bridging problem is caused by near proximity of surface
                      > elements. The relief is higher in these areas. In some cases,
                      > especially
                      > with deep relief printing, this subsurface relief, while it may not
                      > print, will actually show as a slight indent to the paper.
                      >
                      > Often a problem with digital type, regardless of impression, is the
                      > close fitting of certain characters, especially at small sizes. The
                      > relief builds up, providing support, but also increasing the
                      > possibility
                      > of bridging. A solution to this is alteration of the character fitting
                      > at the prepress stage. This problem will also occur in complex fine
                      > line
                      > work in images as well as halftones.
                      >
                      > The photopolymer plate process does have its inherent limitations. The
                      > finest work is going to be achieved by paying attention to this and
                      > working within the latitude of possibility rather than forcing beyond.
                      >
                      > Gerald
                      >
                      > Lisa Davidson wrote:
                      > > Hi, John, Peter, etc.
                      > >
                      > > I totally don't get this, because I mean from a physical standpoint
                      > > you would think that a point source would give a vertical shoulder,
                      > > and a diffuse light source would give an undercut. I mean, the light
                      > > is coming in from all different directions, and if something is
                      > side-
                      > > lighted it ought to be exposed further under. I realize the facts
                      > > are all saying the opposite, but why on earth would that be?
                      > >
                      > > Thank you,
                      > >
                      > > Lisa
                      > >
                      > >
                      > > On Dec 26, 2007, at 8:43 AM, John G. Henry wrote:
                      > >
                      > >
                      > >> The only way to get substantially steeper shoulders in photopolymer
                      > >> platemaking is to use a less diffuse lightsource. When first using
                      > >> photopolymer plates, I exposed the plates using pretty standard
                      > >> exposure frame designed for magnesium and copper plate exposures,
                      > >> using a 5 KW plate exposure lamp. In order to get any angle to the
                      > >> shoulder (the slope on the edge of the image line) I had to use a
                      > >> frosted diffusing film on top of the negative, otherwise the
                      > >> shoulders were almost straight vertical. When producing
                      > photopolymer
                      > >> pattern plates for brass engraving, the steep shoulder was what we
                      > >> desired, but for printing purposes I needed support of the image.
                      > >>
                      > >> The polymer exposure units have been intentionally designed with
                      > >> diffuse fluorescent lighting, to produce that angled shoulder, thus
                      > >> giving better support to fine lines and halftone dots, which
                      > >> otherwise would not take the pressure of printing.
                      > >>
                      > >> In Dow Powderless Etching process for metal plates, the shoulder
                      > can
                      > >> be adjusted by changing the speed of the paddles which flip the
                      > >> acid/oil mixture up to the surface of the plate. The faster the
                      > >> paddle speed, the steeper the shoulders produced. The shoulder
                      > angle
                      > >> is also effected by the strength of the acid/water/oil mixture in
                      > >> the bath.
                      > >>
                      > >> --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...>
                      > >> wrote:
                      > >>
                      > >>> Since the snow white bushy beard is seen about this time of year,
                      > >>>
                      > >> I'll posit my concern about photopolymer 'beards', wondering if
                      > >> there's any technique whereby one can gain a more vertical bite
                      > from
                      > >> photopolymer, more akin to type? As it is, I'm getting a nice depth
                      > >> of impression and a very clean, sharp imprint. For 'cuts' (ie,
                      > >> images) that's all that's required.
                      > >>
                      > >>> However with type, the impression, sharp and crisp as a pink lady
                      > >>>
                      > >> apple on an October afternoon, sits at the bottom of a conical
                      > well,
                      > >> each letter in its own little crater*. With real type or acid-
                      > etched
                      > >> (mag/zinc) plate one doesn't see these craters blending from one
                      > >> letter to the next.
                      > >>
                      > >>> * Note that this is on 300 gsm Crane's Lettra. There is no punch-
                      > >>>
                      > >> through on the verso.
                      > >>
                      > >>> I assume this is due to the spread of the UV into the pp matrix,
                      > >>>
                      > >> which of course is necessary for the strength to hold up fine
                      > >> details etc to the pressure of printing.
                      > >>
                      > >>> My thinking is that it's probably just an inevitable, if
                      > >>>
                      > >> unfortunate, result of the way these plates handle exposure and the
                      > >> water washout. The magnesium plates I get have a very crisp beard,
                      > >> much closer to that of real type. I expect that the acid etching of
                      > >> an opaque metal allows this.
                      > >>
                      > >>> I wonder if there's any way to minimize the angle of the
                      > >>>
                      > >> cone/beard, while maintaining the depth of 'etch' on these plates?
                      > >> I'm currently using Jet plastic-backed plates and the Interflex A4
                      > >> platemaker.
                      > >>
                      > >>> Typical exposure about 3.5 minutes, washout about 5.5 min.
                      > >>>
                      > >>> The only way I can think to minimize this concern would be to move
                      > >>>
                      > >> the lights further from the plate during exposure (ie more of a
                      > >> point light) But this is not an option in the A4 Interflex...
                      > >>
                      > >>> Hmmm
                      > >>>
                      > >>> Merry Christmas to all, Happy Solstice Season!
                      > >>> Best wishes for 2008!
                      > >>>
                      > >>> Peter
                      > >>>
                      > >>>
                      > >>> --
                      > >>> AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
                      > >>> {ARTQ: Help stop in-box bloat! Always Remember to Trim the Quote!}
                      > >>>
                      > >>> ExquisiteLetterpresshttp://www.exquisiteletterpress.com
                      > >>>
                      > >>> -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-
                      > *-:-
                      > >>>
                      > >> *-:-*-:-*-:-*-:-*-:-*-:-*
                      > >>
                      > >>> Peter Fraterdeus http://www.alphabets.com : Sign up
                      > >>>
                      > >> for "MiceType"!
                      > >>
                      > >>> Galena, Illinois Design Philosophy Fonts Lettering
                      > >>>
                      > >> Letterpress Wood Type
                      > >>
                      > >>> Dubuque, Iowa http://www.fraterdeus.com
                      > >>> Photography Irish Fiddle Political Observation
                      > >>> http://flickr.com/photos/pfraterdeus
                      > >>> http://youtube.com/user/pfraterdeus
                      > >>>
                      > >>>
                      > >>
                      > >>
                      > >
                      > >
                      >
                      >
                      >



                      [Non-text portions of this message have been removed]
                    • Peter Fraterdeus
                      Hi Lisa (Thanks, ditto, Gerald for your note) The light comes from all directions, indeed. However, it hardens the polymer in proportion to the exposure.
                      Message 10 of 21 , Dec 26, 2007
                        Hi Lisa

                        (Thanks, ditto, Gerald for your note)

                        The light comes from all directions, indeed. However, it hardens the polymer in proportion to the exposure.
                        Directly under the 'clear' (unexposed) film, it receives the maximum exposure from all angles.
                        The deeper into the polymer, the more limited the exposure to the shallower rays.

                        Therefore a vertical shoulder would, as you say, (theoretically) come from a point source at an infinite distance (like the sun, practically speaking...)

                        However, your second image is incorrect, since the "undercut" is actually an exposure, not a taking away of exposure ;-) Therefore, the ideal 'dot' ideally exposed ends up sitting on a conical base... If you think of the dot as the center of a wheel, the cone is exposed by rays following the 'spokes' from each direction. There is no ray which 'undercuts' the center, it's all additive, so rays which pass beneath the 'center' simply increase the exposure, no?

                        P


                        >...> Hi, John, Peter, etc.
                        >>
                        >> I totally don't get this, because I mean from a physical standpoint
                        >> you would think that a point source would give a vertical shoulder,
                        >> and a diffuse light source would give an undercut. I mean, the light
                        >> is coming in from all different directions, and if something is side-
                        >> lighted it ought to be exposed further under. I realize the facts
                        >> are all saying the opposite, but why on earth would that be?
                        >>
                        >> Thank you,
                        >>
                        > > Lisa

                        --
                        AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
                        {ARTQ: Help stop in-box bloat! Always Remember to Trim the Quote!}

                        ExquisiteLetterpress http://www.exquisiteletterpress.com

                        -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*
                        Peter Fraterdeus http://www.alphabets.com : Sign up for "MiceType"!
                        Galena, Illinois Design Philosophy Fonts Lettering Letterpress Wood Type
                        Dubuque, Iowa http://www.fraterdeus.com
                        Photography Irish Fiddle Political Observation
                        http://flickr.com/photos/pfraterdeus
                        http://youtube.com/user/pfraterdeus
                      • parallel_imp
                        ... polymer in proportion to the exposure. ... exposure from all angles. ... shallower rays. ... come from a point source at an infinite distance (like the
                        Message 11 of 21 , Dec 26, 2007
                          --- In PPLetterpress@yahoogroups.com, Peter Fraterdeus <peterf@...> wrote:
                          >
                          > Hi Lisa
                          >
                          > (Thanks, ditto, Gerald for your note)
                          >
                          > The light comes from all directions, indeed. However, it hardens the
                          polymer in proportion to the exposure.
                          > Directly under the 'clear' (unexposed) film, it receives the maximum
                          exposure from all angles.
                          > The deeper into the polymer, the more limited the exposure to the
                          shallower rays.
                          >
                          > Therefore a vertical shoulder would, as you say, (theoretically)
                          come from a point source at an infinite distance (like the sun,
                          practically speaking...)
                          >
                          I used to use a mercury point light at 18", which needed very long
                          exposures (10-40 minutes), but don't recall ever getting a vertical
                          beard. It would be more likely, I suspect, with thinner plates.
                          On the brands of photopolymer plate I've used, an underexposed
                          isolated dot will be barrel-shaped, not just a steeper cone. Whatever
                          the source or distance, light does diffuse through the photopolymer,
                          and it takes a longer time to build up the bottom of the cone.
                          --Eric Holub, SF
                        • Lisa Davidson
                          Hi, Peter, Right -- exposure hardens, of course, like a filling I got in a tooth once that they illuminated with UV light to make it solid. For heaven s sake.
                          Message 12 of 21 , Dec 26, 2007
                            Hi, Peter,
                            Right -- exposure hardens, of course, like a filling I got in a tooth
                            once that they illuminated with UV light to make it solid.
                            For heaven's sake.
                            Lisa


                            On Dec 26, 2007, at 1:22 PM, Peter Fraterdeus wrote:

                            > Hi Lisa
                            >
                            > (Thanks, ditto, Gerald for your note)
                            >
                            > The light comes from all directions, indeed. However, it hardens
                            > the polymer in proportion to the exposure.
                            > Directly under the 'clear' (unexposed) film, it receives the
                            > maximum exposure from all angles.
                            > The deeper into the polymer, the more limited the exposure to the
                            > shallower rays.
                            >
                            > Therefore a vertical shoulder would, as you say, (theoretically)
                            > come from a point source at an infinite distance (like the sun,
                            > practically speaking...)
                            >
                            > However, your second image is incorrect, since the "undercut" is
                            > actually an exposure, not a taking away of exposure ;-) Therefore,
                            > the ideal 'dot' ideally exposed ends up sitting on a conical
                            > base... If you think of the dot as the center of a wheel, the cone
                            > is exposed by rays following the 'spokes' from each direction.
                            > There is no ray which 'undercuts' the center, it's all additive, so
                            > rays which pass beneath the 'center' simply increase the exposure, no?
                            >
                            > P
                            >
                            > >...> Hi, John, Peter, etc.
                            > >>
                            > >> I totally don't get this, because I mean from a physical standpoint
                            > >> you would think that a point source would give a vertical shoulder,
                            > >> and a diffuse light source would give an undercut. I mean, the
                            > light
                            > >> is coming in from all different directions, and if something is
                            > side-
                            > >> lighted it ought to be exposed further under. I realize the facts
                            > >> are all saying the opposite, but why on earth would that be?
                            > >>
                            > >> Thank you,
                            > >>
                            > > > Lisa
                            >
                            > --
                            > AzByCx DwEvFu GtHsIr JqKpLo MnNmOl PkQjRi ShTgUf VeWdXc YbZa&@
                            > {ARTQ: Help stop in-box bloat! Always Remember to Trim the Quote!}
                            >
                            > ExquisiteLetterpresshttp://www.exquisiteletterpress.com
                            >
                            > -:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-*-:-
                            > *-:-*-:-*-:-*-:-*-:-*-:-*
                            > Peter Fraterdeus http://www.alphabets.com : Sign up for "MiceType"!
                            > Galena, Illinois Design Philosophy Fonts Lettering Letterpress Wood
                            > Type
                            > Dubuque, Iowa http://www.fraterdeus.com
                            > Photography Irish Fiddle Political Observation
                            > http://flickr.com/photos/pfraterdeus
                            > http://youtube.com/user/pfraterdeus
                            >
                            >
                            >
                            >



                            [Non-text portions of this message have been removed]
                          • Gerald Lange
                            Lisa Actually, it is my understanding that with sheet photopolymer the hardness, per se, is already built in (plates have various hardness ratings). Exposure
                            Message 13 of 21 , Dec 26, 2007
                              Lisa

                              Actually, it is my understanding that with sheet photopolymer the
                              "hardness," per se, is already built in (plates have various hardness
                              ratings). Exposure more fixes the imaging in position, after washout and
                              drying post-exposure cures the entirety of the plate (both surface and
                              relief). If anything, it is the drying process that "seemingly" hardens
                              the plate. However, as plates age they quickly start to lose their tack
                              and resilience, and do become brittle. At that point, they are no longer
                              useful for efficient printing.

                              The hardness rating is more an indicator of technical abilities in
                              regard to ink film lay down and transfer, similar to how inking rollers
                              are rated.

                              Gerald

                              Lisa Davidson wrote:
                              > Hi, Peter,
                              > Right -- exposure hardens, of course, like a filling I got in a tooth
                              > once that they illuminated with UV light to make it solid.
                              > For heaven's sake.
                              > Lisa
                              >
                              >
                              > On Dec 26, 2007, at 1:22 PM, Peter Fraterdeus wrote:
                              >
                              >
                              >> Hi Lisa
                              >>
                              >> (Thanks, ditto, Gerald for your note)
                              >>
                              >> The light comes from all directions, indeed. However, it hardens
                              >> the polymer in proportion to the exposure.
                              >> Directly under the 'clear' (unexposed) film, it receives the
                              >> maximum exposure from all angles.
                              >> The deeper into the polymer, the more limited the exposure to the
                              >> shallower rays.
                              >>
                              >> Therefore a vertical shoulder would, as you say, (theoretically)
                              >> come from a point source at an infinite distance (like the sun,
                              >> practically speaking...)
                              >>
                              >> However, your second image is incorrect, since the "undercut" is
                              >> actually an exposure, not a taking away of exposure ;-) Therefore,
                              >> the ideal 'dot' ideally exposed ends up sitting on a conical
                              >> base... If you think of the dot as the center of a wheel, the cone
                              >> is exposed by rays following the 'spokes' from each direction.
                              >> There is no ray which 'undercuts' the center, it's all additive, so
                              >> rays which pass beneath the 'center' simply increase the exposure, no?
                              >>
                              >> P
                              >>
                              >>
                              >>
                              >
                              >
                            • Lisa Davidson
                              Hi, Gerald, I m even more mystified than before! Lisa ... [Non-text portions of this message have been removed]
                              Message 14 of 21 , Dec 26, 2007
                                Hi, Gerald,

                                I'm even more mystified than before!

                                Lisa



                                On Dec 26, 2007, at 5:25 PM, Gerald Lange wrote:

                                > Lisa
                                >
                                > Actually, it is my understanding that with sheet photopolymer the
                                > "hardness," per se, is already built in (plates have various hardness
                                > ratings). Exposure more fixes the imaging in position, after
                                > washout and
                                > drying post-exposure cures the entirety of the plate (both surface and
                                > relief). If anything, it is the drying process that "seemingly"
                                > hardens
                                > the plate. However, as plates age they quickly start to lose their
                                > tack
                                > and resilience, and do become brittle. At that point, they are no
                                > longer
                                > useful for efficient printing.
                                >
                                > The hardness rating is more an indicator of technical abilities in
                                > regard to ink film lay down and transfer, similar to how inking
                                > rollers
                                > are rated.
                                >
                                > Gerald
                                >
                                > Lisa Davidson wrote:
                                > > Hi, Peter,
                                > > Right -- exposure hardens, of course, like a filling I got in a
                                > tooth
                                > > once that they illuminated with UV light to make it solid.
                                > > For heaven's sake.
                                > > Lisa
                                > >
                                > >
                                > > On Dec 26, 2007, at 1:22 PM, Peter Fraterdeus wrote:
                                > >
                                > >
                                > >> Hi Lisa
                                > >>
                                > >> (Thanks, ditto, Gerald for your note)
                                > >>
                                > >> The light comes from all directions, indeed. However, it hardens
                                > >> the polymer in proportion to the exposure.
                                > >> Directly under the 'clear' (unexposed) film, it receives the
                                > >> maximum exposure from all angles.
                                > >> The deeper into the polymer, the more limited the exposure to the
                                > >> shallower rays.
                                > >>
                                > >> Therefore a vertical shoulder would, as you say, (theoretically)
                                > >> come from a point source at an infinite distance (like the sun,
                                > >> practically speaking...)
                                > >>
                                > >> However, your second image is incorrect, since the "undercut" is
                                > >> actually an exposure, not a taking away of exposure ;-) Therefore,
                                > >> the ideal 'dot' ideally exposed ends up sitting on a conical
                                > >> base... If you think of the dot as the center of a wheel, the cone
                                > >> is exposed by rays following the 'spokes' from each direction.
                                > >> There is no ray which 'undercuts' the center, it's all additive, so
                                > >> rays which pass beneath the 'center' simply increase the
                                > exposure, no?
                                > >>
                                > >> P
                                > >>
                                > >>
                                > >>
                                > >
                                > >
                                >
                                >
                                >



                                [Non-text portions of this message have been removed]
                              • richard seibert
                                Seems to me the exposure angle of a well-made plate is a result of the index of refraction of the material. Light travels at different speeds in different
                                Message 15 of 21 , Dec 28, 2007
                                  Seems to me the exposure angle of a well-made plate is a result of
                                  the index of refraction of the material.

                                  Light travels at different speeds in different mediums, so it changes
                                  angle when it enters a new medium.

                                  If one wanted to experiment with steeper shoulders, a higher
                                  frequency (shorter wavelength) light source might do it.
                                • Lisa Davidson
                                  Yikes. What s shorter than UV light that will still harden the pp? Microwaves? ... [Non-text portions of this message have been removed]
                                  Message 16 of 21 , Dec 28, 2007
                                    Yikes. What's shorter than UV light that will still harden the pp?
                                    Microwaves?

                                    On Dec 28, 2007, at 7:34 AM, richard seibert wrote:

                                    > Seems to me the exposure angle of a well-made plate is a result of
                                    > the index of refraction of the material.
                                    >
                                    > Light travels at different speeds in different mediums, so it changes
                                    > angle when it enters a new medium.
                                    >
                                    > If one wanted to experiment with steeper shoulders, a higher
                                    > frequency (shorter wavelength) light source might do it.
                                    >
                                    >



                                    [Non-text portions of this message have been removed]
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