The technical definition of proofreading comes from the publishing and marketing industries. In this arena, the term refers to the examination of a galley proof after it is typeset but before it goes to the printer. Another common definition of proofreading is actually copy editing. The two terms are similar, and many people use them interchangeably. The meanings are different, however, especially for publishers and printers.
Printers work with a variety of documents, including books, brochures, advertising, and manuals. These items start out as drafts that can include writing, artwork, charts, and graphs. Proofreaders do not check these materials for errors. That is the responsibility of a copy editor. In fact, a document may be edited multiple times before the proofreader ever sees it.
Editing involves close examination of a draft copy, looking for errors, including misspelled or misused words, improper grammar, typos, and poor content. A copy editor is responsible for catching all of the errors before the proof goes to the proofreader. Publishers and printers want that galley proof to be as close to perfect as possible.
Proofreading enters the picture after the document has been edited and sent to be typeset. The typesetter provides a printed copy of the manuscript or document to the proofreader to be carefully examined for text and art errors. The proofreader verifies that all edits have been made and makes certain there are no errors that will result in production problems.
The process of proofreading a galley proof may involve two people or at least two copies of the document. The proof is compared to the edited copy to make sure they match. The proofreader looks for art and text errors that can potentially throw off the entire publication. Glaring mistakes in artwork, graphics, or charts may be pointed out during proofreading, but the time for typos is usually over when the galley proof gets to the proofreader.
Outside of the printing and publishing industries, many people define proofreading as checking a written document for errors. Although this is actually copy editing, the terms are regularly given the same meaning. The goal of proofing or editing at this stage is to find errors in a particular document, manuscript, or other written material.
The biggest differences between the two terms are that proofreading involves a typeset document that is being printed on a large scale. Copy editing can be done on any type of document, even if the end product is only going to one individual. A proofreader typically compares the proof he or she is working on to an edited copy that has been marked up with proofreaders’ marks. A copy editor usually works with the original draft copy only, and scans it to find errors and items that should be changed.