Vector Drawings and
When you want to create a drawing that
can be placed in a program like Quark or InDesign, you have
two options. You can create a bitmapped drawing composed
of printer dots, or you can create a vector drawing made
up of PostScript curves, points, and lines.
A vector drawing produced in a program
such as Adobe Illustrator (as opposed to a bit-mapped image
produced in Photoshop) is made up of curves and control
points. Essentially, it is a mathematical formula that will
print a series of shapes, whereas a bit-mapped image is
a checkerboard of pixels that create a pattern or shape
by being either on or off (black or white). The advantage
of a vector image is that it can be scaled up (enlarged)
without loss of detail and will print at the highest resolution
of the imagesetter, platesetter, or laser printer to which
it is downloaded (unlike a raster image—bit-map—which
will display an increasingly evident jagged edge as it is
enlarged further and further).
The control points of such a vector
image can be problematic. If your drawing has too few, it
will lack detail. A complex shape will become a simple (and
perhaps unusable) shape if too many control points are removed.
(A rectangle, for instance, might become a triangle if one
of the control points is removed. A heart shape might become
an unintelligible blob if too many control points are removed.)
If, on the other hand, your drawing
contains too many points, it can slow down or disable the
imagesetter or platesetter by taxing the RIP (raster image
processor), the software or hardware interpreting device
that translates the mathematical curves and shapes of PostScript
into a final bitmap of "on" or "off"
spots on the imaging substrate (plate or film).
There are ways to minimize these problems.
Your vector image program (Illustrator, Freehand, Corel
Draw, etc.) has a “flatness” setting that allows
you to adjust for this variable. Setting this variable to
the optimal amount of points will allow you to print an
image that has sufficient detail but that doesn't slow down
or choke the RIP.
Another approach to this issue is to
be aware that PostScript, the computer language that creates
the shapes of the letters and images on your page, defines
curves as a series of straight lines as it rasterizes the
file for printing on an imagesetter or platesetter. A circle,
for instance, is made up of lots and lots of adjoining straight
lines. The more straight lines that make up your circle,
the less evident their straightness is, and the smoother
the circle appears. The smoothest circle would be composed
of the largest number of short line segments (which to the
naked eye would become so small as to be invisible), yet
printing such a circle would slow down the RIP dramatically,
particularly if the circle contains a gradient fill.
When printing curved shapes or type,
increase the flatness value of your vector objects created
in Illustrator by entering a number in the Output text box
smaller than the existing number. To determine the flatness
at which an object prints, divide the printer resolution
by the object's output resolution. For example, an object
with an 800 dpi output resolution prints to a 2400 dpi imagesetter
with a flatness of 3 (2400/800 = 3). Since the flatness
value determines how smoothly a curve will be printed, if
you use a flatness level that is too high, the line segments
making up the curves may be visible. Testing may be required.
Also, you may want to have your print provider check a sample
of your work.
It is prudent to check the output resolution
setting in Illustrator. You may, in fact, need to lower
this number to get a graphic to print on your laser printer.
However, if you need to change the number to get the image
to print, remember to reset the output resolution to 800.
You may need to test the file at this point before sending
it to your offset printer.
Can't Find the Right Colored Paper Stock?
You find the perfect color of paper
for your job but none of the paper swatch books from the
paper mills include a swatch of exactly the right color.
Or, you find the perfect paper in the swatchbook, but your
printer says you have to order a huge amount to meet the
mill’s minimum paper order requirement. Or it might
take the printer two weeks to get the paper, and you need
the printed job in a week.
What do you do?
If you had planned to print your job
on a small press (black text only on both sides of an 11”
x 17” sheet folded to a four-page 8.5” x 11”
job, for instance) on that seafoam green paper you loved
and can’t get, you will probably have to move to a
larger press and “paint the sheet.” That is,
you can choose a PMS color that matches the paper you love
but can’t get. You will cover the sheet entirely (heavy
coverage with bleeds, which justifies the larger press because
it will produce cleaner solids) and print the black text
on the seafoam green background. No one but you will know
that the sheet did not come from the paper mill in exactly
that shade of green.
As with most things in printing, quantity
controls the price. If you are already printing on a larger
press (perhaps due to the size of your printed sheet), painting
the sheet might cost 33 percent more than just printing
the black text on the existing stock. This is due to your
using more ink and wasting more paper in makeready. If,
on the other hand, you had planned to print the job on a
small press (a duplicator), but your decision to paint the
sheet has necessitated your moving up to a larger press,
your bill might be double what it would have been on the
Finally, if you are tempted to
choose a darker green and have the printer screen it back
and bleed the color on all four sides, be careful. You may
not like the outcome. A screened back color may look totally
different than you had envisioned. It may appear to have
a completely different hue and value. Only a 100 percent
solid of a PMS can exactly match the swatch in your Pantone
Matching System book. If you can’t find the exact
color you want, check out Pantone’s pastel or metallics
books, since they also contain 100 percent PMS solid colors.
[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]