Proofreading means reading printed copy and marking any errors found in it. When a body of type is set, the typesetter prints a proof (trial copy) from it. The proofreader then compares the proof with the original manuscript, marking any errors with a set of symbols called proofreaders' marks. The proofreader makes one mark in the copy to identify the location of the correction. A corresponding mark is made in the margin to specify the kind of correction needed. The proofreader reads carefully, looking for any misspellings, mistakes, or broken type. The proofreader also reads with an awareness of content, questioning anything inconsistent. When working with publications typeset on desktop computers, the proofreader must also check for correct alignment and positioning of borders and pictures.