ICC color management can match color, pixel by pixel, from the source color space to the destination color space. The degree of color match is limited by the repeatability of the device and color management constraints between the source and destination. This research outlines a method whereby printing and proofing can be simulated visually and quantitatively. Major findings indicate that (1) the simulation error at the device level is about 1 ?E00 at the 95th percentile of the sample distribution; (2) the error at the color management workflow level, except special causes, is about 2 ?E00 at the 95th percentile of the sample distribution; (3) gamut clipping, due to CIE-b* difference or CIE-L* difference, is a special cause that contributes to proof-to-print mismatch. Avoiding gamut clipping by choosing the proofing substrate close to the white points of the printing paper, but with more "head room," is a key finding in this study. In addition, we need no fewer than two proofing stocks to choose from. This is because the OBA difference between a proof and a print is an indication of the criticalness of the M1 lighting, i.e., the match becomes more metameric when the OBA difference is high.