#New DTP'r questions/pt2
7 messages in this thread
Brad,
If pre-press compiles elements of the page for the printer, what
information is added by the service bureau that is not provided by Quark
Xpress? Is anything other than higher resolution provided by the
typesetter (do I call people who run the image setting equipment
typesetters?) that is not in the computer generated file of the page which
the DTP designer provides?
Why do image setter's like Linotronic produce higher resolution than is
possible with the laser printers?
Is the problem with color standard a problem of translation from the
computer to the image setter, or is it a problem with lack of a standard
for different brands of image setters?
Here's any easy one ( I think): does the typestter run the imagesetter from
a screen and keyboard which allows him to preview the layout?
The trapping problems with colors wihich overlap: is that caused by the
overlays for the four colors not being able to overlay in alignment because
they try to occupy the same space? I don't really understand.
What is RC paper? Is output to paper only for proofing purposes? In other
words, is everything eventually put on film? Is film negative the stage
before going to metal ? If so, what is the pupose of film positive?
All things being equal on a page, which would output faster 1270 dpi or
2540 dpi?
And finally: why not invite more "freelance hacks" to get involved in this
type of interchange and then using the results to create a library file to
help us all help each other? You all are a substantial source of
information and obviously what we called "good folk" when I was a boy
growing up in Indiana. Oh, and by the way, I've been known to bitch and
moan myself. Quite healthy, if not overindulged in, in my opinion.
Dennis,
(Before I begin, I have a correction: Rag (or "ragged") Right means the
right hand edge of a column is unevenly set, not the other way around, as I
said in my previous message.)
A laser printer places electric charges on a drum, to which toner sticks
and is then transferred to paper and "fused" to it at high temperatures.
Repro (or Resin Coated paper), which is the most common output from an
imagesetter, is specially treated paper that is exposed to light and then
developed (much like the film in a camera). A negative of this repro then
has to be shot before making plates for the printing press. Sometimes it's
OK just to run negs on a Lino, but it can be twice as much as running
repro, so you have to make sure that you're not going to have to re-run
your pages (which often enough happens in the real world). It's also harder
to proofread from the negatives, and you may not even save enough at the
printers to warrant the extra cost. And if you want to use the repro to
build mechanicals (manually adding other, non-electronic, elements to the
page), then that's the way to go.
(Some of my clients like to run film positives for their separations so
that they can build overlays for the printer, something that they (and the
printer) are familiar with.)
The term "typesetter" can mean the person setting the type or the machine
you output the type to. These days, we talk about using "imagesetter,"
though, as often more than type is being output. And PostScript, the page
description language, is doing a lot more than typesetters (with their
master code for each letter of a font) did. Since 2,540 x 2,540 (1,000 mm x
1,000 mm) of info per square inch is a heck of a lot more that 1,270 x
1,270, a page will take longer to image.
I'm going to move this message thread into Section 8 (The Learning Curve)
now, and will, indeed, capture it for inclusion in Library 8 (Forum
Transcripts) before it scrolls off the board. BTW, what part of Indiana are
you from? I lived in Terre Haute for 3-1/2 years and Indianapolis for 2-1/2
years.
<BW>
The more I read that last message, the more it appears I said that 1 inch
equals one meter. I gotta stop leaving long messages after midnight!
Brad,
So the service bureau basically adds higher resolution, and converts the
page to printer ready form? Any other benefits?
Can anyone explain why an imagesetter produces higher resolution than a
laser printer?
Do different brands of imagesetters adhere to a uniform color standard?
Specifically, would a graphic's color look the same if output with
different brands of imagesetters all other things (resolution) being equal?
How about some info. on various trapping problems and how to avoid them?
I grew up in Tri-Lakes, Indiana, which is near Columbia City, which is near
Fort Wayne. My brother lives in Indianapolis. Have you got a basketball
hoop on your garage?
–Dennis
Dennis,
Actually, providing higher resolution output is a very important service in
and of itself. These imagesetters cost around $65,000, and that doesn't
include the cost of a developer, chemicals, film, etc. Since the
imagesetter directly exposes the RC paper (repro) or film directly to laser
light, the resolution can be very fine. Laser Printers are limited by the
size of the toner particles that can legally be used, and firmly attached,
to a piece of plain paper.
Some service bureaus also have other expensive equipment, such as color
laser printers, stat cameras, scanners and workstations where you can rent
time on their machines so that you can work on your own stuff. I suspect
that some will even act as printer brokers and help you take a project all
way through to completion. And imagesetters don't do anything in color;
it's all black and white. If you're working in color, you need to either
output to a laser printer (usually just for comps–and don't ask me what
comp means) or output separate "plates" of black and white repro or film
that will then be used by the printer to produce color pages.
You should probably check out the thread in Section 13 (Printing &
Prepress) called "Print 1 color ovr anothr" for an interesting discussion
about color trapping.
<BW>
P.S. Since I live in an apartment in NYC, I don't have a basketball hoop,
or a garage, or a car for that matter! I left Indiana about 8 years ago.
Brad,
I appreciate the quality and need for higher resolution output. I just
want to get a clearer picture of what is being done and how. I suspected
finer toner and special paper were part of the answer. What about the
difference in the hardware? If a laser printer puts electrical charges on
a rotating drum, how does an imagesetter work? Is it like a camera or a
photocopier? I don't want a technical answer, just the general principle.
What does the stat camera do?
Who knows what comps are? Does it have the same meaning as proofs? ( I
know you said not to ask, but I'm hoping someone else will know.)
Thanks for the info. on color. I have read at least part of the thread
"print 1 color ovr anothr." Interesting. They mention overprinting.
What's that? Also, if immagesetters don't provide color, how is proofing
done for color? Does postcript provide the information for the color
specifications of is that handled by the graphics program? And is there a
common standard which allows me to create specific colors on the page with
my computer, which, even though the colors might not be exacty reproduced
on screen, or on a color laser printer, will print true on a printing
press?
Sorry to hear you have no place for a hoop. Prehaps you can get one for
the wastebasket. My wife grew up in Stonybrook on the island.
Imagesetters don't use toner. They use a laser to expose resin coated
paper, which is developed much like the film in a camera.
The graphics program keeps the color info, and allows you to output
separate "plates" to an imagesetter. The printer then uses these different
pieces of film to produce his "plates" which are placed in the appropriate
place in the printing process so that only a certain color is printed for
certain areas of the page.
A stat camera is used for making a one piece shot of a mechanical made of
many pieces, or to make a negative of a positive mechanical.
Comps are, indeed, proofs, often showing all the color pieces of a page.
You show them to customers to give them a better idea of what they'll be
getting once the page is printed, but they cost a heck of a lot less than
setting up a press just to produce one copy of something.
Overprinting is, basically, printing one color on top of another. Sometimes
it's desirable, sometimes not. Color is not my specialty, I'm afraid.
Standards are coming into existence on desktop machines foe separating
colors, but we're not out of the woods, yet. Aldus has proposed OPI; Quark
has proposed DCS. I don't know a thing about either. The safest colors to
ask for in a graphic program are Pantone colors. Use a swatch book of PMS
(Pantone Matching Systems) colors, assign the PMS color in your file,
output the colors separately for each page, and tell the printer which
plate gets which Pantone color.
<BW>