Printing presses had been around for a while, but printing really took off after Gutenberg invented moveable type. Printing presses can generate many images on paper very quickly compared to drawing each one by hand. Suddenly ordinary people could afford to own books—and navigators could afford to have maps when they sailed.
The first printed maps were woodcuts—what’s called relief printing. This is when you take a flat piece of wood and trace the drawing onto it backwards; you carve away everything that isn’t the drawing; you roll ink onto the wood and press it onto a piece of paper; the ink leaves an impression on the paper. Showing longitude & latitude lines on a woodcut map wouldn’t be easy, because you have to carve wood away leaving the line.
Much better for accurate mapmaking was engraving. With this kind of printing, you take a flat piece of copper and draw lines onto it with a steel stylus. Steel is much harder than copper, so the stylus cuts a precise, v-shaped groove. When the drawing is finished, you rub ink all over the copper plate and into the grooves. Wipe the surface clean and leave the ink in the grooves. Run the copper plate with a damp piece of paper through a tight press and the ink stays on on the paper.
When the paper dries, you can feel the ink lines—they stand up. American paper money is engraved. You can feel the lines on a brand-new dollar bill. Copper is durable so you can make gazillions of copies from one plate.
Back to the beginning of The Western Civ User’s Guide to Time & Space