Working without a previous version, proofreader marks typographical errors in printouts, typeset galleys, or page proofs. Tasks may include extensive querying of usage, spelling, grammar, punctuation, style, and format. Tasks may also include verifying facts or performing a light pre-press check. Proofreader will use standard proofreading marks to fix typographical errors, poor type quality, format problems, or deviations from specifications. Subsequent sets of proofs will require the proofreader to correct a typeset (or live copy) printout by comparing it with a previous version (dead copy).