Historically, proofreading was performed by reading galley proofs or page proofs that came from the typesetter. A galley is a storage repository for type pages and a galley proof is a copy of the composed type (while it is on a galley) in straight column format on a roll of cheap paper. Type size and column width match the final format, but the pages are not cut to size. A page proof, on the other hand, is a copy of the composed type in page-layout form. Modern printing relies on computer technology for the preparation of printed materials. Instead of galley proofs, proofreaders use page proofs in Portable Document Format (PDF).

Regardless of the methods used to create the proofs, proofreading is strictly speaking a function of the production processes. As such, proofreading differs from editing, which is part of the processes to prepare the manuscript for production. A result of this difference is that proofreaders work with desktop-publishers instead of authors and focus only on mechanical aspects, such as page layout, typographical errors, and wrong fonts. Editors also check the correctness and proper arrangement of the underlying information.

Occasionally, proofreaders might flag factual errors in proofs. It is not too late to correct these errors because Bibilioso handles production processes electronically, but apart from critical errors, content should be regarded as final at this point. It is very costly to rewrite content in the proofreading stage. Most production processes would then have to be repeated for parts or the entire material. Not only do costs increase because of this repeated work, but also the publication date is jeopardized. Even small delays in production schedules often result in substantial delays to the final publication because busy printers schedule their work far ahead.

In documentation projects with an extremely tight budget, authors may be able to assume the proofreader role. However, authors have a tendency to rewrite content when exposed to their page proofs, thus jeopardizing project budget and schedule. To avoid this risk, we recommend using a dedicated proofreader instead.