Photographic proofs with a distinctive blue colour used to check that elements such as copy and photos are correctly incorporated into a document and to show that folding, trimming, and other bindery processed are correctly understood by the print shop. Also known as dylux, blues, browns, brownlines, silvers, vandykes, and ozalids.

Photographic prints made from negatives (or positives) of text or artwork, used for final proofing before a publication goes to press.

Also referred to as "Blues." This printer's photocopy generated by the printer is a blue-print mock-up of all of the pages of the book printed from the final plates. Bluelines allow a final opportunity to detect errors and make minor corrections before the book goes to press. If changes are needed, they have to be made to the film, which can be expensive.

A contact proof created from the film used to verify that the film is correct. The word comes from the blue paper used by most printers.

A magazine proof printed in a single shade of blue that is also printed, folded, and bound to approximate what the finished magazine will took like. Changes made after an approval is often costly.

The printer's photocopy or blue print mock-up of the book's pages. These are used by traditional publishers to detect errors and make corrections. On-demand publishing uses a Proof that is a copy of the actual book.