Antique maps are a particularly fascinating area of collecting, as they present to the eye directly something of the way in which people in history in different countries saw the world.
Sometimes it is astonishing how accurate the details are when the maps pre-date regular travel, never mind aerial photography. In other cases it is interesting to see where the limitations are. Often too, early maps can be very beautiful.
For the most part, collectable maps date from the invention of the printing press in the 15th century. Before this, maps were hand-drawn on vellum, and these would often be used for exploration, hence few survive.
But how do you go about printing a map, or anything else? There are three broad classes of printing: Relief, Intaglio and Planographic.
In relief printing the image is formed by pressing paper against a raised, inked surface, such that ink which is not on the intended image for printing cannot reach the paper. Two examples are woodcut and wood engraving.
In wood engraving, the image is carved into the block's side, into the softer horizontal grain. All areas that should not print are cut away. The block is comparable to a rubber stamp, and they tended to create heavy lines. Schedel was a well-known map-maker who made early use of woodcuts in map-printing.
Wood engraving, sometimes confused with intaglio, carves the required image out of the hard end of the wood using an engraving tool such as a burin. It is still the raised surface which presses ink to paper however.
Intaglio printing is the exact opposite of relief printing. The image is carved into the printing plate or block, probably a metal plate, rather than being left behind when the carving is done. The plate is then inked and that ink is wiped from the raised surfaces so that it remains only in the recesses.
Paper is then pressed against the plate, at a higher pressure than for relief printing (for which reason some printing which involved both text and maps used two different presses.
Examples of Intaglio are etching and engraving. Engraving is the more straightforward: a process by which a design or image is cut into a metal plate using a burin or graver. Most intaglio prints produced before 1900 were engravings.
Etching is done by using acid to 'cut' the metal for you. A layer of acid-resistant wax is applied to a metal plate and an etching needle is used to draw a design in the wax before it is dipped in acid, eating into the unprotected areas of metal.
Early etching was used for armour, and later in the 17th century the technique was used artistically by Rembrandt. But it could be used to produce finely drawn maps too.
As we've looked a printing using both raised and flat plates/blocks there is only one variation to go: flat plate printing. In planographic printing, chemicals do the work of distinguishing the image from background. Unlike etching, the plate's levels are not changed at all.
An example of planography is lithography - invented some time after the printing press, at the turn of the 18th to the 19th century. 'Lithography' literally means 'stone writing' as limestone was originally used to print from.
The technique used wax or an oily substance to draw the image on stone, and then applies an oily-ink and water mixture to the surface. Famously oil and water do not mix, and the oily-ink 'prefers' the wax whilst the water goes to the 'background' areas of the plate, creating an image for printing.
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