++CMYK Separation Settings in i1 Match
Q - What do the CMYK "Select your separation" options do in i1 Match?
A - The i1 Match CMYK Printer profiling module offers 8 separation options. These options offer varying combinations of gray-component replacement (GCR) or undercolor removal (UCR), black start point, maximum black, and total ink coverage. Since all of these options affect the relative proportion of CMYK printing inks, they can only be used with CMYK-mode profiles, which are those intended for use with a CMYK PostScript RIP. These options are not available in the RGB Printer module because RGB-to-CMYK conversion is done in the printer driver, not the RIP or application.
The CMYK Printer options are:
Liquid Ink Jet 260. GCR4, black start 40, maximum black 100, total ink coverage 260
Liquid Ink Jet 400: GCR3, black start 40, maximum black 100, total ink coverage 400
Solid Ink Jet: GCR3, black start 40, maximum black 100, total ink coverage 360
Thermo Dye Transfer: GCR4, black start 0, maximum black 85, total ink coverage 385
Offset: GCR2, black start 0, maximum black 95, total ink coverage 320
Gravure: UCR, black start 60, maximum black 100, total ink coverage 400
Newsprint: GCR4, black start 5, maximum black 95, total ink coverage 240
Laser: GCR MaxK, black start 5, maximum black 100, total ink coverage 400
The meaning of these settings is:
GCR: Gray component replacement, a process that replaces CMY inks throughout the tone scale with black where they produce gray. Higher GCR levels indicate that more CMY is replaced with K in grays.
UCR: Undercolor removal, a process that reduces CMY inks in shadows and increases black to compensate.
Black start: This is the %C dot at which K starts printing as a 1% dot.
Maximum black:This is the largest-size black (K) dot that is produced.
Total ink coverage: Sum of CMYK inks, theoretically 400% maximum.
The optimum value depends on the type of printing process and paper.