Proofs form part of the contract between printers and their customers. Even some experienced print buyers don't know how to inspect or mark a proof up though! Here are some guidelines: Physical   Is the job the right size, the right number of pages, and can you understand how it will be finished? Always inspect the proof first of all with a ruler. Often it can help to draw a pen rule around the final trim of the job, so you can easily check the bleeds and the page elements are as they should be. Digital proofs will be supplied with pre-printed page rulings. Content   Check that paragraph and page endings are where you expected them to be. Make a visual comparison of fonts, font weights and font sizes. Ensure that each picture is properly positioned, and that colours are accurately reproduced. Textual   Even at this late stage you may find textual errors in your work. With digital proofs these are simple and inexpensive to put right. If you have machine proofs, the cost of corrections will be considerable. None the less, it is always worth checking a a minimum:   Prices Phone and fax numbers – dial them to check them That the last few corrections have been made Machine proofs   If you have paid to have machine proofs it is always worth making up a dummy copy of the finished document. We can produce this on your behalf if requested. If your job uses special colours, check the colours carefully, and also check that the stock is the correct stock for your job. Mark up   Mark your proofs up clearly, with a brightly coloured pen. If you have any concerns at all about the work in front of you, you should mark them on the proof. If you have textual amendments to request, please use BS5261 proof correcting marks where possible. A good summary of these can be viewed here. About PDF proofs   Increasingly work is proofed by PDF - especially work destined for digital production. PDF proofs should be inspected with the same rigour as any other kind of proof. You should generally print them and inspect them, rather than inspect them only the screen. If you are reading them on the screen, view the file at a large size. We are happy to accept your comments or approval embedded in an Acrobat file emailed back to us.