DOES THE GREYSCALE MONITOR CALIBRATION USE ICC PROFILES?
No. Photoshop 4 included a great CMYK onscreen preview (called a soft proof). This was primarily used by printers with CMYK printers such as the Iris printer. Photoshop 5.x added ICC workflow, but the only image preview that was available was for CMYK. Photoshop 6 finally added softproofing preview capability for RGB files. The ICC workflow automates the preview function. Small patches of color (our ICC profiles measure 750 patches) are measured using expensive photospectrometers, and a numeric table is created that defines the color as measured and the CIE Lab equivalent. This numeric table is called an ICC profile. Photoshop and other ICC aware applications can use this set of numbers to accurately display onscreen the colors as they will be printed, assuming that the monitor has also been measured and profiled. Before there was anything called an ICC workflow, people still managed to print successfully. In Photoshop 4, you could manually define a custom set of numbers for CMYK print
