Graphics Programs Reference
In-Depth Information
About spot and process colors
A spot color is a special premixed ink that is used instead of, or in addition to,
CMYK process inks. Each spot color requires its own printing plate on a printing
press,sousespotcolorwhenfewcolorsarespecifiedandcoloraccuracyiscritical.
Spot color inks can accurately reproduce colors that are outside the gamut of pro-
cess colors. However, the exact appearance of the printed spot color is determined
by the combination of the ink as mixed by the commercial printer and the paper
it's printed on, not by color values you specify or by color management.
A process color is printed using a combination of the four standard process inks:
cyan,magenta,yellow,andblack(CMYK).Useprocesscolorswhenajobrequires
so many colors that using individual spot inks would be expensive or impractical,
as when printing color photographs.
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For best results in a high-quality printed document, specify process colors us-
ing CMYK values printed in process color reference charts, such as those
available from a commercial printer.
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The final color values of a process color are its values in CMYK, so if you
specify a process color using RGB (or LAB, in InDesign), those color values
are converted to CMYK when you print color separations. These conversions
differ based on your color-management settings and document profile.
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Don't specify a process color based on how it looks on your monitor, unless
you are sure you have set up a color-management system properly and you un-
derstand its limitations for previewing color.
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Avoid using process colors in documents intended for onscreen viewing be-
cause CMYK has a smaller color gamut than that of a typical monitor.
Sometimes it's practical to use process and spot inks in the same job. For example,
you might use one spot ink to print the exact color of a company logo on the same
pages of an annual report where photographs are reproduced using process color.
You can also use a spot-color printing plate to apply a varnish over areas of a pro-
cess color job. In both cases, your print job would use a total of five inks—four
process inks and one spot ink or varnish.
—Condensed from InDesign Help
