A proof is a common concept in "offset" printing where a printer is working with a complex layout (like stationary, business cards, etc).
Our online order wizard has a 'download proof' button in the layout screen of the wizard where you layout your uploaded image. This proof is a color, clarity, size, and layout proof of what your print will look like when you receive it, so be sure to download and check it.
We don't provide additional 'print ready' proofs because all we would be doing is sending you back a JPG image of exactly what you upload to us, there wouldn't be a change. The PDF proof available from the order wizard is the best and only proof we can provide.
We print your image exactly the way you send it, there are no changes or editing, making tradtional 'press proofs' unnecessary. Our printers and screens are Pantone color calibrated so the printed poster will match the colors as closely as possible in a printing process.