CHAPTER 4
272
Graphics
TABLE 4.21 Entries in a DeviceN color space attributes dictionary
KEY
TYPE
VALUE
Subtype
name
dictionary
(Optional; PDF 1.6)
A name specifying the preferred treatment for the color
space. Possible values are
DeviceN
and
NChannel
. Default value:
DeviceN
.
(Required if
Subtype
is
NChannel
and the color space includes spot colorants; other-
wise optional)
A dictionary describing the individual colorants used in the
DeviceN
color space. For each entry in this dictionary, the key is a colorant name
and the value is an array defining a
Separation
color space for that colorant (see
given in that color space.
This dictionary provides information about the individual colorants that may be
useful to some applications. In particular, the alternate color space and tint trans-
formation function of a
Separation
color space describe the appearance of that
colorant alone, whereas those of a
DeviceN
color space describe only the appear-
ance of its colorants in combination.
If
Subtype
is
NChannel
, this dictionary must have entries for all spot colorants in
this color space. This dictionary may also include additional colorants not used
by this color space.
Colorants
Process
dictionary
(Required if
Subtype
is
NChannel
and the color space includes components of a pro-
cess color space, otherwise optional; PDF 1.6)
A dictionary (see Table 4.22) that de-
scribes the process color space whose components are included in this color
space.
(Optional; PDF 1.6)
A dictionary (see Table 4.23) that specifies optional attributes
of the inks to be used in blending calculations when used as an alternative to the
tint transformation function.
MixingHints
dictionary
A value of
NChannel
for the
Subtype
entry indicates that some of the other en-
tries in this dictionary are required rather than optional. The
Colorants
entry
specifies a
colorants dictionary
that contains entries for all the spot colorants in
the color space; they are defined using individual
Separation
color spaces. The
Process
entry specifies a
process dictionary
(see Table 4.22) that identifies the pro-
cess color space that is used by this color space and the names of its components.
It must be present if
Subtype
is
NChannel
and the color space has process color
components. (An
NChannel
color space may contain components from at most
one process color space.)