Reading proofs of edited manuscript. Galley proofing may include incorporating and/or exercising discretion on author's alterations; flagging locations of art and page references; verifying computer codes. Page proofing may include checking adherence to mock-up (rough paste-up), accuracy of running heads, folios and changes made to type in mock-up, checking page breaks and location of art, and inserting page numbers to table of contents and cross-references if necessary. May also include checking vandykes and colour mats (press proofs).
Definition taken from Editors' Association of Canada.