Before printing, producing copies of written materials could be done; it was just time very time-consuming and expensive. A copy of a book or manuscript did not need to look exactly the same as the original—the words just needed to be the same. Thus, while printing was revolutionary in terms of written materials due to the massive decrease in price it brought with it, this was not something fundamentally new that printing allowed.
However, printing did for the first time allow for the creation of many accurate copies of illustrations, something that was near impossible prior to its invention. Take this excerpt from a 1876 atlas of Baltimore, for example.
Even if one were to tracing it, which would severely restrict one’s paper choices, one would be hard pressed to produce a close copy. Creating the map likely took days or weeks of work after the data had already been collected. Drawing an exact copy, however, would be extremely difficult, and would likely take even longer. Hand copying an atlas with maps of this detail would make copying the Bible look easy in comparison.
While printing was an incremental, though enormous, improvement for copying written works, it allowed accurate copies of illustrations for the first time. Text takes it meaning from its words and not so much how it looks, but illustrations depend very much on their appearance. Thus, while printing’s ability to quickly and cheaply make copies was revolutionary, what was even more revolutionary was the uniformness of these copies.