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972
CHAPTER 10 Document Interchange
KEY TYPE VALUE
DestOutputProfile stream (Required if OutputConditionIdentifier does not specify a standard
production condition; optional otherwise) An ICC profile stream
defining the transformation from the PDF document’s source
colors to output device colorants.
The format of the profile stream is the same as that used in spec-
ifying an ICCBased color space (see “ICCBased Color Spaces” on
page 252). The output transformation uses the profile’s “from
CIE” information (BToA in ICC terminology); the “to CIE”
(AToB) information can optionally be used to remap source
color values to some other destination color space, such as for
screen preview or hardcopy proofing. (See implementation note
168 in Appendix H.)
Note: PDF/X is actually a family of standards representing varying levels of con-
formance. The standard for a given conformance level may prescribe further restric-
tions on the usage and meaning of entries in the output intent dictionary. Any such
restrictions take precedence over the descriptions given in Table 10.51.
The ICC profile information in an output intent dictionary supplements rather
than replaces that in an ICCBased or default color space (see “ICCBased Color
Spaces” on page 252 and “Default Color Spaces” on page 257). Those mechanisms
are specifically intended for describing the characteristics of source color compo-
nent values. An output intent can be used in conjunction with them to convert
source colors to those required for a specific production condition or to enable
the display or proofing of the intended output.
The data in an output intent dictionary is provided for informational purposes
only, and PDF consumer applications are free to disregard it. In particular, there
is no expectation that PDF production tools will automatically convert colors
expressed in the same source color space to the specified target space before gen-
erating output. (In some workflows, such conversion may, in fact, be undesirable.
For example, when working with CMYK source colors tagged with a source ICC
profile solely for purposes of characterization, converting such colors from four
components to three and back is unnecessary and will result in a loss of fidelity in
the values of the black component; see “Implicit Conversion of CIE-Based Color
Spaces” on page 259 for further discussion.) On the other hand, when source
colors are expressed in different base color spaces—for example, when combining
separately generated images on the same PDF page—it is possible (though not re-
quired) to use the destination profile specified in the output intent dictionary to
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