A proof is a typeset version of copy or a manuscript page. They often contain typos as a result of human error. Traditionally, a proofreader looks at an increment of text on the copy and then compares it to the corresponding typeset increment, and then marks any errors (sometimes called ‚line edits‘) using standard proofreaders‘ marks. Unlike copy editing, the defining procedure of a proofreading service is to work directly with two sets of information at the same time. Proofs are then returned to the typesetter for correction. Correction-cycle proofs will typically have one descriptive term, such as ‚bounce‘, ‚bump‘, or ‚revise‘ unique to the department or organization and used for clarity to the strict exclusion of any other. It is a common practice for ‚all‘ such corrections, no matter how slight, to be sent again to a proofreader to be checked and initialed, thus establishing the principle of higher responsibility for proofreaders as compared to their typesetters or artists.
Style guides and checklists
Proofreaders are expected to be consistently accurate by default because they occupy the last stage of typographic production before publication.
Before it is typeset, copy is often marked up by an editor or customer with various instructions as to typefaces, art, and layout. Often these individuals will consult a style guide of varying degrees of complexity and completeness. Such guides are usually produced in-house by the staff or supplied by the customer. When appropriate, proofreaders may mark errors in accordance with their house guide instead of the copy when the two conflict. Where this is the case, the proofreader may justifiably be considered a copy editor.
Checklists are common in proof-rooms where there is sufficient uniformity of product to distill some or all of its components to a list. They may also act as a training tool for new hires. Checklists are never comprehensive, however: proofreaders still have to find all mistakes that are not mentioned or described, thus limiting their usefulness.