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Step:
Indicates the degree to which components (such as CMYK values) of abutting
colors must vary before InDesign creates a trap. Type a value from 1% to 100%, or use
the default of 10%. For best results, use a value from 8% to 20%. Lower percentages
increase sensitivity to color differences and result in more traps.
Black Color:
Indicates the minimum amount of black ink required before the Black
Width setting is applied. Type a value from 0% to 100%, or use the default of 100%. For
best results, use a value no lower than 70%. See “Trapping with blacks and rich blacks” in
the
Adobe InDesign CS User Guide
or online Help.
Black Density:
Indicates the neutral density value at or above which InDesign considers
an ink to be black. For example, if you want a dark spot ink to use the Black width setting,
enter the neutral density value here. Use any value from .001 to 10, but this value is typi-
cally set near the default of 1.6.
Sliding Trap:
Indicates the percentage difference between the neutral densities of abut-
ting colors at which the trap is moved from the darker side of a color edge toward the
centerline, creating a more elegant trap.
Trap Color Reduction:
Indicates the degree to which InDesign uses components from
abutting colors to reduce the trap color. This is useful for preventing certain abutting
colors (such as pastels) from making an unsightly trap that is darker than either color.
Specifying a Trap Color Reduction smaller than 100% begins to lighten the color of the
trap; a Trap Color Reduction value of 0% makes a trap whose neutral density is equal to
the neutral density of the darker color.
Assigning trap presets
You can assign a trap preset to a document or a range of pages in a document. While it might
be easier to apply a trap preset to the entire document uniformly, your workflow may benefit
from applying no trap preset to specific spreads where trapping isn’t necessary. Pages with
no abutting colors will print faster if you disable trapping on those pages by applying No
Trap Preset in the Trap Presets palette. Trapping doesn’t actually occur until you print the
document.
