Traditionally, proofreading was the comparison of two versions of a document, one marked-up for correction and the other incorporating those corrections and this remains one of the functions of a proofreader.
In more modern terms, proofreading generally means the reviewing of a single version of a document in either hardcopy (printed out) or softcopy (electronic/on screen) to identify and correct errors in spelling, punctuation, grammar, line and paragraph spacing, ‘widows’ and ‘orphans’, plus consistency of numbered and bulleted lists, paragraph alignment, tables, page numbers, headers and footers etc …
A word on ‘spell checkers’ in word processing programmes. These are ‘OK’, as far as they go, but will not differentiate between the different spellings (and intended usage) of common words – for instance : by, bye and buy; sent, cent and scent; for, four and fore. A number of ‘poems’ demonstrating this have been written and several are included in the ‘Lighter Moments” section of this site. Also, by default (ie when installed using the ‘standard’ settings) most word processing software (or any other software actually), spell checks according to an American English dictionary – fine if that is what you want, but if your intended audience uses UK English it will effectively either leave you with or create spelling errors.
In short, spell checkers, by themselves, should not be trusted to properly ‘proofread’ your work.
Documents provided to TPE in hardcopy (print only) will be proofread and marked-up using standard proofreading symbols. A report will also be provided explaining both the symbols themselves and the corrections / suggested corrections indicated.
Documents provided to TPE in softcopy (electronic) will be proofread twice, once on screen and once from a printout. Documents able to be read in either Microsoft Word or Adobe Acrobat will be marked-up and commented using the ‘Track Changes' and 'Comments’ functions of those programmes. Output will include both electronic and printout versions of the documents concerned.
If requested, text can be ‘extracted’ from PDF documents and reviewed in Microsoft Word. Alternatively, TPE does have software available which emulates most of the functions of a word processing programme to review and amend PDF documents in their native format.