For both printers and clients, accurate proofs are needed before going to press. The proof should predict what the job will look like on the press. Press proofing is an integral part of the printing process. It is important to customers that the colors on a digitally printed proof will match the colors printed on an offset press. The Larry Brink Printing Laboratory at Western Michigan University uses a Xerox Docucolor 12 for printing proofs for a Shinohara offset press. This project examines digital color proofing the offset press. In order to accomplish this, an ICC profile target was printed on multiple substrates on the offset press and the digital printer. These were measured to create output profiles for the two devices on the different substrates. These profiles were used to simulate the offset press with the digital printer. The proof was verified both numerically and visually. The experimental procedure, results and reasons for differences are discussed.