Choosing to proceed without a proof is a option to choose if the colour accuracy isn't important, and your comfortable knowing the files supplied are correct and suitable for high quality printing.

Choosing a PDF proof confirms the file uploaded is correct. Not the best solution for colour accuracy, but great for content, and confirming the file uploaded is correct and suitable for high quality printing.

This option is the best for making sure the colour and content are correct. Please note the hard copy proof is produced on a digital printing press, which may differ slightly from the production press. So colour accuracy rangers form 80-100%. Your CSR can explain how accuracy the proof colour will be.