Re: Photopolymer Optimization of letterforms
- Dear David
Thanks for the return post. I would very much like to see your sample
output. I think letterform optimization is a crucial aspect of getting
photopolymer to print as if it were metal type. Lots of folks don't
understand this and then blame the process. So thanks for bringing it
The Bieler Press
4216 1/4 Glencoe Avenue
Marina del Rey, CA 90292
>...I've wondered for a long time if I was the only person bothered by
> the fat appearance of most polymer type. It is refreshing to hear
> in this discussion group that there are other people out there with
> similar concerns.
> With regards,
The proofs are on their way, via USPS. I live in northern Vermont, so
they probably won't arrive in your mailbox until the middle of next
--- In PPLetterpress@y..., "Gerald Lange" <bieler@w...> wrote:
>Thanks for the return post. I would very much like to see your
>sample output. I think letterform optimization is a crucial aspect
>of getting photopolymer to print as if it were metal type. Lots of
>folks don't understand this and then blame the process. So thanks
>for bringing it back up.
- Dear David [Wall]
Thanks for sending the proofs. These look quite good. I've got some
Is the -.064 choke normative or maximum? How much further could you
choke before you experience letterform breakup?
I assume this is possible in PageMaker, Illustrator, InDesign as well,
do you know?
Does this effect leading or other page parameters; line length, text
block measure, etc? From the proofs I'd quess not, correct?
What are the difficulties encountered in explaining the trapping to
the folks at the service bureau (film house)?
Think this may be a useful technique. Thanks.
David P. Wall wrote
When first experimenting with polymer letterpress several years ago, I
discovered that there are also ways to "negative trap" or "choke" the
type in QuarkXPress to compensate for ink squeeze and some of the
vagaries of using a single master type pattern for multiple sizes of a
computer typeface. The process is not quite as simple as spreading the
text for offset printing, and I've found that not all film houses are
interested in working through the somewhat strange parameters. But if
you can find a film house that is willing to work with you, the
results are remarkably satisfying....
.... you can negative-trap blocks of text-size type, or display or
even rules, and probably some line art depending on how the art image
files are formatted. Where multiple sizes of type appear one page, you
have the flexibility to apply a different trap to size, so that you
can even-out the overall color of the page. Basically (in QuarkXPress)
you create a solid-colored background behind the text, trap the
background to the text (by choking it in on the text), and then use a
positive of the background (with the text knocked out of it) as a
negative to make the polymer plate. Sounds simple, right? Maybe not,
but once you get used to the way it works, it really is pretty simple
(albeit somewhat more time-consuming than just sending an un-trapped
file to the imagesetter). If you'd like to see some proofs of a test
page trapped to varying degrees, let me know. I've still got a few
sheets in my files....
I've wondered for a long time if I was the only person bothered the
fat appearance of most polymer type. It is refreshing to in this
discussion group that there are other people out there similar
concerns. Will this negative trapping technique work on large blocks
I'm glad you like the proofs. In response to your questions:
> Is the -.064 choke normative or maximum?The -.064 choke is neither normative nor maximum. It just happens to
be what gave the best overall effect for that particular test page.
For best results I think you should apply less choke to smaller sizes
of type, and more to the larger, and it bears some experimentation
with the amounts applied to different typefaces. I found that
the "gain" from my laser printer (relative to the high resolution of
an imagesetter) roughly mimics the gain from letterpress, and it is
therefore possible to experiment first with laser proofs before
wasting a lot of expensive film and plate material.
> How much further could you choke before you experience letterformThe amount of additional choke that can be applied depends both on
the specific typeface design, and on the size at which you are
reproducing it. Smaller types, and those with finer lines, will start
to break up before the larger sizes and heavier designs. Quark allows
a choke of up to -36 points---three whole picas!---which is obviously
far more latitude than we need for this purpose. In most cases I
would think an appropriate amount of choke for a text face would be
between -0.100 and -.008 points, depending on the size and the design.
> I assume this is possible in PageMaker, Illustrator, InDesign asI do not have first-hand experience in trapping/choking with these
> well, do you know?
programs, but they undoubtedly must all have some sort of function
for addressing trapping of colors to one another. If so, they can
probably be adapted to choke the text the same way that it works in
> Does this effect leading or other page parameters; line length,The choking/trapping does not have any significant effect on line
> text block measure, etc?
length or text block size. It basically is just the reverse of the
gain that you get from ink squeeze on press.
> What are the difficulties encountered in explaining the trapping toThe problem that I encountered with one film house was just in trying
> the folks at the service bureau (film house)?
to make it clear to them what I wanted the final output to look like.
It can be confusing because what you need is positive film of the
colored background (this is what has the choked type knocked out of
it), which will end up looking kind of like a negative piece of film.
And of course, the film also needs to be right-reading/emulsion-up.
For most service bureaus it should not be a problem if you ask them
for RREU Positive film of the color channel. If they are outputting a
file that you prepared yourself, they should not need to do anything
with regard to the trapping/choking. (Note that you do not want film
for the black channel, even though this is technically the channel
with the type in it.)
I hope this is making some sense to everyone. It is much easier for
me to explain in person, where I can draw diagrams and use hand
gestures. I will gladly try to answer more questions if you have them.
With best regards,