Adobe Acrobat XI - Manual (Page 545)

538
Print production tools (Acrobat Pro)
Last updated 1/14/2015
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.
Trap thresholds
Step Specifies the color change threshold at which the trapping engine creates a trap. Some jobs need only the most
extreme color changes trapped, while others require traps for more subtle color changes. The Step value indicates the
degree to which components (such as CMYK values) of abutting colors must vary before trapping occurs.
To change how much the component inks in abutting colors can vary before causing those colors to trap, increase or
decrease the value for Step in the New Trap Preset or Modify Trap Preset Options dialog box. The default is 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 trap width setting is applied. The
default value is 100%. For best results, use a value no lower than 70%.