Digital proofs for packaging are used in the industry as a means of showing the buyer what the finished artwork will look like on their packaging. (EPSON proofs) Digital proofs are printed in the preferred screen ruling (dots per cm/inch) of the printer. These proofs are generally very good for giving you an accurate idea of the printed result, but they are to all intents and purposes, only an accurate approximation. (It remains possible that the odd unexpected things can show up in the print that are not visible on the proof.)
Improvements in colour management technology allow digital (dot) proofs to serve as contract proofs.