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3. Specify the following options, and then click OK.
•
For Name, type a name for the preset. You can't change the name of the [Default] trap
preset.
•
For Trap Width, type values to specify the amount of overlap for inks. Values up to 8
points can be used by Adobe In-RIP Trapping; values will be limited to 4 if you use
built-in trapping. Default applies to all colors except black, and Black applies to solid
black areas. You control what InDesign considers solid black by setting the Black Color
and Black Density options in the Trap Thresholds section of this dialog box.
•
For Trap Appearance, specify options for controlling the shape of the outside join of
two trap segments and the intersection of three traps. The choices in the Join Style
pop-up menu are the same as in the Stroke palette. The default is Miter, which maintains
compatibility by producing the same trapping results as earlier versions of the Adobe
Trapping Engine. The End Style controls the intersection of three traps. The default is
Miter, which shapes the end of the trap to keep it away from the intersecting object, while
Overlap wraps the end of the lightest trap (as defined by neutral density) around the
point where the three objects intersect.
•
For Images, specify settings that determine how to trap imported bitmap images:
Trap Placement: Provides options for determining where the trap falls when trapping
vector objects (including objects drawn in InDesign) to bitmap images. All options
except Neutral Density create a visually consistent edge. Center creates a trap that
straddles the edge between objects and images. Choke causes objects to overlap the
abutting image. Neutral Density applies the same trapping rules as used elsewhere in
the document. Trapping an object to a photograph with the Neutral Density setting can
result in noticeably uneven edges as the trap moves from one side of the edge to another.
Spread causes the bitmap image to overlap the abutting object.
Trap Objects to Images: Ensures that vector objects (such as frames used as keylines)
trap to images, using the Trap Placement settings.
Trap Images to Images: Turns on trapping along the boundary of overlapping or abut-
ting bitmap images.
Trap Images Internally: Turns on trapping among colors within each individual bitmap
image (not just where they touch vector artwork and text). Use this option only for page
ranges containing simple high-contrast images, such as screen shots or cartoons. Leave it
unselected for continuous-tone and other complicated images, as it will create bad traps.
Trapping is faster when this option is unselected.
Trap 1-Bit Images: Ensures that 1-bit images trap to abutting objects. This option does
not use the Image Trap Placement settings because 1-bit images use only one color. In
most cases, leave this option selected. In some cases, such as a 1-bit images where pixels
are widely spaced, selecting this option may darken the image and slow trapping.
•
For Trap Thresholds, type values to specify the conditions under which trapping occurs.
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