Proofreading has existed since the invention of the printing press. Its earliest mention was in a 1499 printing contract that placed responsibility for proofreading on the author, sixty years after Johannes Gutenberg invented the modern movable type in 1439.
For many years, comparison proofreading was standard. A single proofreader compared the original text with the typeset, mechanical, or proof and marked any discrepancies in the drafts with proofreader's marks. Another method required two people: the copyholder with the original text, and the copyreader with the typeset, mechanical, or proof. The copyholder read the original text out loud, and the copyreader compared and marked any errors with proofreader’s marks. These methods are still used in some publishing houses, but noncomparison proofreading is more common today with digital text.
Noncomparison proofreading consists of a single proofreader marking copy with a pen or annotating digital copy with corrections and comments within the text. Nancy uses the digital method at Pine Tree Proofreading.