PeaRl Of WISDOm
Although I don’t want to engender fear of the Custom CMYK dialog
box, I caution you to regard most of its controls as off-limits. This is
especially true of the Separation Options at the bottom of the dialog
box, which are based on attributes of the printing press that you could
not possibly know unless you were to use it yourself or interview
someone who does. I discuss a couple of these options, GCR and Total
Ink Limit, in the sidebar “Why (and How) Three Channels Become Four,”
on page 492. But with the exception of Name, there’s really only one
subjective option in the dialog box: Dot Gain.- Adjust the Dot Gain value. With very few exceptions,
commercial presses use small circles of colored ink, called
halftone dots, to impart different shades of color. Dark
areas get big dots; light areas get small dots. Illustrated
in Figure 12-18, the term dot gain refers to how much the
halftone dots grow when they’re absorbed into the paper.
The Prints-R-Us profile includes a Dot Gain value of 35
percent, which means the print house anticipates that its
halftone dots will grow 35 percent when printed on a specific
grade of paper. Obviously, there’s a mistake here; if the dot
gain were really 35 percent, the image would tend to print
dark, not overly light, as it did for us. So the current Dot
Gain value is overcompensating.
Figure 12-18.Magnified CMYK halftone dots If the dots grow, the image darkens438 Lesson 12: Print and Web Output