Wordsage offers the following Proofreading Services:
A proofreader marks typeset copy word for word against a manuscript, identifies deviations for correction, and queries editorial errors. Proofreaders may also check copy for conformity to type specifications, create a style sheet [see sample] and ensure attractive typography by checking kerning, margins, word spacing, repetitive word breaks, and the like. If a proofreader is not given copymarked manuscript to refer to when proofing final materials, it can be referred to as “blind” or “cold” proofreading.
An editorial proofreader combines proofreading with some copyediting tasks, if they are needed late in the production process. This can include correcting errors such as misspellings, typos, misnumbering or mislabeling, subject-verb disagreement, word usage (such as the use of imminent for eminent), and identifying incorrect or outdated cross-references. If copy is missing, the proofreader requests the copy. Editorial proofreading may also involve typemarking, and making marginal notes to show the first citation of illustrations, tables, and other display elements. If instructed, single quotation marks are changed to double quotation marks as needed in running text and in displayed extracts. When the manuscript consists of typeset text, the proofreader checks for incorrect word breaks.
At this level, the editorial proofreader adds punctuation to delineate a restrictive clause only if the change will prevent confusion, retains secondary spellings and the existing footnote or endnote system, and does not tamper with word choice or marginally incorrect punctuation (such as semicolons in a simple series) unless requested to do so.
Publishers often request editorial proofreading when previously published material is to be reprinted, or when there are concerns about possible input errors in material that has been heavily edited or drastically reformatted.
A fact checker does not make editorial changes, but simply verifies the accuracy of content as specified by the publisher. One client may request that the fact checker verify all statements, while another client may request the verification of addresses and trademarks only. The publisher specifies the degree of accuracy required.
(Sourced from Bay Area Editors’ Forum.)