The images below walk you through the process of printing 2-color,
double-sided business cards on a Vandercook SP-20 printing press. They
were designed for a wedding photography company called
Readyluck, by Baltimore designer
Christopher Clark. These cards were printed on Crane Lettra 220 lb Pearl White cotton paper.
This is the Vandercook SP-20. In this press’s first life it probably
pulled proofs of pages for a daily newspaper. Today, these presses are
sought after for their quality and large printing size.
Polymer plates are produced using a photographic process. The
digital design is output to a film as a negative (left), and then
exposed to a polymer plate using UV light (right). The polymer plate is
made of a light-sensitive, water-soluble plastic with a clear backing.
The portions of the plate that are exposed through the clear parts of
the film hardens, and what is not washes away. What remains is a raised
surface in the shape of the design. A separate plate is produced for
every
color being printed, and the paper is run through the press at least
once for each color in the design. We send our designs to
Boxcar Press, where they transfer your digital design onto a polymer plate. These plates match a gridded Boxcar Base, a machined aluminum plate that raises the plate to type high.
The plate is affixed to a machined metal base which is in turn locked into the press.
Ink is mixed by hand. When possible, ink can be weighed out to match
a specific color recipe, but in our shop we mix everything by eye,
often matching to a specific Pantone color. We use oil-based,
lithography inks.
The press is inked. Even the inking process has to be done
carefully. Too much ink will produce a sloppy print. Too little, and
the color will not be solid.
Printing begins. This plate prints an area half the size of the
sheet. The sheet of paper is hand-fed through the press twice, once
from each end of the paper. This produces 8 cards per sheet in a
process called a work-and-turn. The 220 lb Crane Lettra paper, double
than the standard 110 lb weight (and more than twice the cost), allows
for a deeper impression on both sides, which was desired by the client.
The ink is allowed to dry and the next day the press is inked up in
red. Differences in pressure and the amount of ink can dramatically
affect the printed color. Adjustments are made to produce the desired
color, and the print run is checked periodically to be sure the color is
consistent. For this particular run, the red ink ran out relatively
quickly and frequent re-inkings were required.
All presses have a system of registration. Consistent placement of
every print on every sheet is a must for quality printing. This design,
like most we produce, has cross-hair trim marks made into the plate
that serve not only as cutting guides, but printing guides as well.
After this print run dried, a third printing run was made on the
reverse of the pages.
Cutting! Printing is finished and the job
is ready to cut. We usually die cut our business card jobs, even when
the job doesn’t call for an unusual shape. Our business card die cuts
four cards in a single pass. The press is outfitted with a metal
die-jacket for protection, and the die itself is made up of metal
cutting blades surrounded by protective foam pads. (Ed. Note: We’ll be covering die cutting in greater detail tomorrow!)
Each pass on the press cuts four cards. While this is an extremely
inefficient press for die cutting, its accuracy far out-weighs speed for
us.
The design for these cards utilized a random, non-repeating pattern
and intentionally transparent colors. The four cards together create
one overall design, but each business card is unique.
(http://ohsobeautifulpaper.com/2012/01/the-printing-process-letterpress-printing/)
