Adobe InDesign CC 2015 - Manual (Page 606)

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Printing
Last updated 6/6/2015
4 Click Assign, and then click Done.
To disable a trapping page range, choose Assign Trap Preset in the panel menu, type a page range, and choose [No Trap
Preset] in the Trap Preset menu. Click Assign, and then click Done.
Trap preset options
You can change trap preset options whenever you create or edit a trap preset. The same trap preset options are available
in Acrobat and InDesign. In Acrobat, you can view trap presets by choosing Tools > Print Production > Trap Presets.
In InDesign, choose Window > Output > Trap Presets.
Trap widths
Trap width is the amount of overlap for each trap. Differences in paper characteristics, screen rulings, and printing press
conditions require different trap widths. To determine the appropriate trap widths for each job, consult your
commercial printer.
Default Specifies the trap width in points for trapping all colors except those involving solid black. The default value is
0p0.25.
Black Indicates the distance that inks spread into solid black, or the holdback amount—the distance between black
edges and underlying inks for trapping rich blacks. The default value is 0p0.5. This value is often set to be 1.5 to 2 times
the value of the default trap width.
In InDesign, the value you set for Black Color determines the value for a solid black or a rich black, a process black (K)
ink mixed with color inks for increased opacity and richer color.
Note: (InDesign) If you choose Application Built-In trapping, and you specify a Default trap width or Black trap width
larger than 4 points, the resulting trap width is limited to 4 points. However, the value you specified will continue to be
displayed, because if you switch to Adobe In-RIP Trapping, traps larger than 4 points are applied as you specified.
Trap appearance
A join is where two trap edges meet at a common endpoint. You can control the shape of the outside join of two trap
segments and the intersection of three traps.
Join Style Controls the shape of the outside join of two trap segments. Choose from Miter, Round, and Bevel. The
default is Miter, which matches earlier trapping results to retain compatibility with previous versions of the Adobe
Trapping Engine.
End Style Controls the intersection of three-way traps. Miter (the default) shapes the end of the trap to keep it away
from the intersecting object. Overlap affects the shape of the trap generated by the lightest neutral density object that
intersects with two or more darker objects. The end of the lightest trap is wrapped around the point where the three
objects intersect.