Printing Maps
Once information has been gathered and organized, and a map designed, the next step is printing. Antique maps were printed
using one of three methods. In all cases the design was placed on the printing surface mirror-image, so that when it was printed
the map would be seen as the cartographer intended. The three methods are:
Relief - the design is raised on a block, it is inked and then printed using a press. Most blocks were wood and the design was
put on the block by cutting away the parts that would not be printed. Modern rubber stamps are a form of relief printing.
Blocks were usually of fruit woods such as cherry. Other woods were either too hard to work with or too soft to last long.
Maps and prints made from such blocks are often called woodcuts.
Woodcut map of Africa
Intaglio - the design is cut into a metal plate using a sharp tool known as a burin. Inking the plate is more complex than with
a relief block. First the plate is warmed so ink will run into the grooves, then the entire plate is covered with ink, and finally it is
wiped clean so the only ink remaining is in the grooves.
A special press is required for printing from plates. It consists of two rollers which are close together, much like the old-
fashioned clothes-wringer. Paper is dampened so it will be flexible in the press, placed on the plate, and then the paper
and plate are run through the press. Pressure from the rollers forces the paper down into the grooves, which also causes the printed
lines to be slightly raised. (Modern raised printing is done by a different method, but is an attempt to imitate the effect of raised
lettering which was on early calling cards printed from an intaglio plate.)
The plate usually was of copper, hence the term copperplate engraving. Copper was soft enough to take the design easily, but
hard enough so that several hundred to a few thousand impressions could be made before it wore out. In the 19th century
techniques were developed for softening steel so it could be engraved upon, and then hardening the steel so many thousands of
impressions could be printed from the plate.
Engraved map of Spain
The earliest printed maps were made in the 15th century and both of the above methods were used from the start. Engraving
gradually became the technique of choice probably because it was easier to modify a metal plate than a wood block. In order
to change a block, one had to saw out the section to be changed and insert a replacement. With a metal plate, one tapped out
from behind the area to be changed so it was raised. Then the old design was rubbed out and a new design engraved.
In the 19th century new methods began to be used.
Planigraphic - the design is created on a flat surface such as a stone, and chemical processes are used to hold the ink in place.
Paper is pressed on to the stone and the ink is transferred to the paper.
Lithography is an example of planographic printing. It was invented in the late 1700's. The design would be put on a specially
prepared stone using a greasy pencil. The stone would be inked and then washed to remove excess ink. The only ink
remaining would be that which adhered to the greasy marks. Then a paper would be placed on the stone and an impression
taken. Within a few decades of its invention, lithography was being used to print maps and atlases.
Lithographic map of Pennsylvania
At this time virtually all maps were printed black and white. Color was applied by hand using watercolors. Color printing became practical in the late 19th century.
Maps were usually printed on paper. Other materials such as cloth or animal skin were used occasionally. Specially
treated skin (called vellum or parchment) was sometimes used for maps that would be subject to hard use (such as charts that were
going to sea) or for special presentations. However, the skin was expensive to make, irregular in shape, and difficult to print on
so its use was limited.
Most maps were printed on paper. The paper was made by hand from cloth (usually linen) rags which were cut into small
pieces, put in a liquid bath and beaten so the fibers broke down. A rectangular frame with wire mesh (called a deckle) was
dipped into the liquid and a layer of fiber was lifted out on the mesh. It was allowed to drain, placed on to felt, and covered
with another layer of felt. Thus, layers of felt and paper would alternate. The next step was to put the alternating layers into a
press to remove more water. Then the paper would be air-dried, and finally treated with size to give it body.
A group of maps could be bound together to create an atlas. In early times, there was no such thing as standard publisher's
binding and the loose sheets would be sold by a bookseller to a customer who would then take it to a binder. Before binding
maps would be folded and a binder's guard of paper would be pasted to the back of the map at the back or verso of the
centerfold. The guard would be used for sewing the book, so that when the map was open the center would be visible to the
user of the atlas. Also, there would not be stitch holes in the map.
The size of a piece of paper was limited by the size deckle that one workman could hold. Large maps were created by printing
and then joining several sheets. Often large maps would be given a backing of cloth to strengthen them. The map could then be
attached to rollers and used as a wall map. In other cases, a large map would be cut into convenient-size sections before being
backed. Then it was easy to fold the map for storage.
|