Details:
Summary:
Having a calibrated monitor with an accurate ICC monitor profile is a necessary, but not sufficient condition for an accurate soft proofing system. Soft proofing, using a computer monitor to proof a printed piece on a conventional or digital printing press, is an increasingly important component for remote proofing of mission critical printed materials. Soft proofing systems are current issues for proposed revisions of SWOP. This paper examines the requirements for an accurate, useful and certifiable soft proofing system. The accuracy of a monitor profile depends on both the stability of the monitor and the accuracy of the measuring device used to build the profile. In addition to an accurate monitor profile, the accuracy of a soft proofing system depends on the CMM (Color Management Module) utilized, the specified white point (color temperature) and, of course, how well the profile represents the device it is attempting to characterize. Results of colorimetric measurements using various emissive spectrophotometers are presented for CRT and LCD displays of controlled color patches in RGB, CMYK and Lab modes. The accuracy of these values, predicted from the profile versus measured, is highly dependent on the CMM employed. Surprisingly, the accuracy of the soft proof is highly dependent on the method used to display the soft proof. There are three different, a priori equivalent, and methods to display a soft proof using Photoshop. Only one of these gives colorimetric agreement with printed and Info Palette values. Care must be taken when interpreting displayed Lab or CMYK values. Differences between CRT and LCD monitors are discussed. A summary of unresolved issues and some recommendations for their resolution is presented.