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     CHAPTER 10                                                       Document Interchange



     • The Web Capture plug-in extension (Section 10.9), which creates PDF files
       from Internet-based or locally resident HTML, PDF, GIF, JPEG, and ASCII text
       files
     • Facilities supporting prepress production workflows (Section 10.10), such as
       the specification of page boundaries and the generation of printer’s marks, color
       separations, output intents, traps, and low-resolution proxies for high-resolution
       images


10.1 Procedure Sets

     The PDF operators used in content streams are grouped into categories of related
     operators called procedure sets (see Table 10.1). Each procedure set corresponds
     to a named resource containing the implementations of the operators in that pro-
     cedure set. The ProcSet entry in a content stream’s resource dictionary (see Sec-
     tion 3.7.2, “Resource Dictionaries”) holds an array consisting of the names of the
     procedure sets used in that content stream. These procedure sets are used only
     when the content stream is printed to a PostScript output device. The names
     identify PostScript procedure sets that must be sent to the device to interpret the
     PDF operators in the content stream. Each element of this array must be one of
     the predefined names shown in Table 10.1. (See implementation note 159 in
     Appendix H.)

                             TABLE 10.1 Predefined procedure sets
     NAME                 CATEGORY OF OPERATORS

     PDF                  Painting and graphics state

     Text                 Text

     ImageB               Grayscale images or image masks

     ImageC               Color images

     ImageI               Indexed (color-table) images

     Note: Beginning with PDF 1.4, this feature is considered obsolete. For compatibility
     with existing consumer applications, PDF producer applications should continue to
     specify procedure sets (preferably, all of those listed in Table 10.1 unless it is known
     that fewer are needed). However, consumer applications should not depend on the
     correctness of this information.

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