4-Color Process Vs. Spot Color Printing
When combined, the four process
inks--cyan, magenta, yellow, and black, or CMYK for short--can
produce a wide range of colors, often far more than you
will need for your project. However, if you must match a
specific color, let’s say for a logo, in some cases
the process “build” of that color will be muddy.
It will lack clarity and crispness.
In these cases you may choose to add
a fifth or sixth color. This color will be premixed from
a “recipe” listed in a Pantone, Trumatch, or other
spot color chart or book. With this Pantone or Trumatch
book you can communicate the percentage components of your
color accurately to any offset printer.
Keep in mind that the press on which
your job will be printed must have an adequate number of
units. For instance, a job composed of four process colors,
a fifth spot color, and a varnish can be printed on a six
color press or on a four-color press with a wash-up between
printing the process colors and the spot colors. Regardless,
adding a spot color can significantly drive up the cost
of the job.
Also, when choosing both process colors
and additional spot colors, make sure you note which is
which in your page-composition software. Quark, for instance,
provides a “spot”/“process” dialog box
for this distinction. If you mistakenly define a spot color
as a process color, the software will separate the color
onto the four process plates when you print your job. Just
to make sure, print a proof of all separations before you
send your job to press. If you have a sheet of paper for
each process color and also a sheet of paper for each spot
color--with the proper elements on each--you’re ready
to go.
One final note: Choose both spot colors
and their process equivalents from a current Pantone swatch
book that specifically notes both Pantone spot colors and
their nearest four-color matches. These books also note
the percentage of CMYK needed to create the color you have
chosen. Exposure to light changes these color swatches over
time, so, to be safe, replace your books yearly.
Keep in mind that this conversion can
go both ways. If you have a specific color you want to match
and you want to limit your color palette to the four process
colors to control costs, you may find that the four-color
equivalent noted in your swatch book actually does come
very close to the spot color you have chosen. If this is
the case, you may be able to keep your job on a four-color
press, which would cost less per hour than the six-color
press you would need to print an additional spot color.
Web Vs. Sheetfed Printers
Depending on the length of your press
run, your print job will be produced on either a web (roll-fed)
or sheetfed press. It pays to learn what equipment your
printers have on the pressroom floor--and hence what kinds
of jobs your printers focus on--since most printers do not
have both web and sheetfed capabilities.
As a rule, web presses are best suited
for longer runs. Web presses run at much higher speeds,
and most have some finishing capabilities (folding, gluing,
etc.) at the delivery end of the press. Whereas a press
sheet comes off a sheetfed press as a large, flat sheet
of paper, a web press may deliver a complete, folded signature,
ready for binding. This can speed up the entire production
process significantly.
Sheetfed presses are best suited for
shorter runs and where showcase quality is required. Sheetfed
presses can also run heavier paper, and conversely web presses
can run newsprint or other thin paper. Some sheetfed presses
can turn the sheet over within the press and print both
sides in one pass. However, all web presses must perfect
(print both sides at once), since it would be nearly impossible
to run the roll of paper through the press a second time
while achieving close register.
As a general rule, consider a web press
when the number of impressions exceeds 25,000. Remember
that a brochure that would fit “six-up” on a sheet
would count as 1/6 of 25,000 impressions. If you are confused
as to which press would be more appropriate, bid out your
job to both web and sheetfed printers.
[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.]