Proofreading is the process of reading a text and scrutinizing all of its components to find errors and mark them for correction. It is done after a manuscript has been converted to a format for publication but before it is published.* A thorough proofread is done in eight stages or passes:
ONE: First Read-through
This stage addresses errors in spelling, grammar, punctuation, and consistency. The proofreader checks to see if the material makes sense and that the ideas are presented clearly and concisely.
TWO: Chapter Numbers and Titles
The proofreader checks that the chapter numbers and titles are in order, and have the same typeface, size, and placement.
The proofreader checks that all headings of the same level have the same typeface, size, and placement.
FOUR: Numbered and Bulleted Lists
The proofreader checks that all numbers in each list are in consecutive order and have the same spacing, typeface, size, and placement.
Art captions, figure captions, and table captions are checked for consistency and accuracy at this stage.
SIX: Running Heads and Folios
The proofreader checks the running heads and folios (page numbers) to make sure that sequential page numbering is correct.
SEVEN: Table of Contents
The proofreader checks that the Table of Contents reflects all the material accurately. Page numbers and chapter titles are reviewed.
EIGHT: Final Review
At this final stage, the proofreader considers how the material looks. Are there any areas of blank space? Is the spacing between headings and text equal? Are there any very short lines of text?
*(Sourced from Go Ahead . . . Proof It! by K.D. Sullivan)
Editorial proofreading 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subject-verb disagreement, word usage (such as the use of imminent for eminent), and identifying incorrect or outdated cross-references.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. 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)