Adobe InDesign CC 2015 - Manual (Page 612)

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Printing
Last updated 6/6/2015
Trapping text
Both the Adobe In-RIP and built-in trapping engines can trap text characters to other text and graphics. (Built-in
trapping requires that the text and graphics are created with InDesign, and aren’t contained in imported graphics.) A
text character overlapping different background colors traps accurately to all of the colors.
Adobe In-RIP Trapping can trap all types of fonts. In contrast, built-in trapping works best with Type 1, OpenType, and
Multiple Master fonts only; using TrueType fonts may result in inconsistent traps. If your document must use TrueType
fonts and you want to use built-in trapping, consider converting all TrueType text to outlines by selecting the text and
choosing Type > Create Outlines. The text will become InDesign objects that trap reliably. Text can’t be edited after you
convert it to outlines.
Maximizing trapping performance
Whether you use Adobe In-RIP trapping or built-in trapping, you can save time by not processing pages that don’t need
trapping, such as pages containing black text only. You can use trap presets to enable trapping only for the page ranges
that require it.
The speed with which built-in trapping is accomplished depends on the speed of your computer system. If you’re
trapping every page of a long document, use the fastest computer system you have. Built-in trapping also makes
extensive use of your computer’s hard disk, so a fast hard disk and data bus will benefit the built-in trapping engine.
To maximize the time your computers are available for other tasks, consider using Adobe In-RIP Trapping, which
processes all traps at the RIP, instead of at your computer.
Setting aside disk space for built-in trapping
To trap the edges of every color that requires trapping, the trapping engine creates a large number of paths that are used
only by the output device (the paths are not stored in your document). While Adobe In-RIP Trapping processes and
stores these additional paths at the RIP, built-in trapping uses your computer’s hard disk as a temporary storage area for
these trap paths. Before you use built-in trapping, make available as much hard disk space as possible.
The amount of disk space you’ll need depends on a wide range of factors, so it isn’t possible to predict exactly what a
particular trapping job will require. However, disk space requirements are most likely to increase when one or more of
the following characteristics of your document increase:
• Number of pages included in trapping page ranges.
• Number of overlapping color objects.
• Number of images that need to be trapped.
• Amount of text that needs to be trapped.
• Resolution of final output.