“…printed books are often deficient in spelling and appearance. The simple reason is that copying by hand involves more diligence and industry.” - (p. 475) Trithemius, Writing Materials
It’s strange to think of people worrying that printers would make spelling errors and typos, but not scribes. I would imagine that humans would be more likely to make mistakes, and not machines. They just weren’t ready to give up the control they had over information.
A human using a printing press would first have to set the type (that is, arrange all the little separate letter-shapes to get them ready for the ink that will be transferred to the page), and I think that is the point where the errors come in.
I know I make dozens of mistakes when hand-writing. My notes from classes are very detailed, but have a lot of white out spots and scribbled out words (the perfectionist in me). I would think that since it was such a process to insert all the letter shapes, people would be more careful about the ordeal.
But I guess that if you made a mistake in a hand-written book, the mistake would be less harmful to the public (becuase it's only one book)than if a bunch of books from the press contained mistakes and were then distributed. Especially history books
Technology, such as the printer, is liable to make mistakes. "To err is human", I disagree with that because things that are not human are bound to screw up. Technology is not perfect.