CHAPTER 6
506
Rendering
The colorants or color components represented in a type 5 halftone dictionary
fall into two categories:
•
Primary color components for the standard native device color spaces (
Gray
for
DeviceGray
;
Red
,
Green
, and
Blue
for
DeviceRGB
;
Cyan
,
Magenta
,
Yellow
, and
Black
for
DeviceCMYK
;).
•
Nonstandard color components for use as spot colorants in
the native color space is nonstandard.
Separation
and
DeviceN
color spaces. Some of these may also be used as process colorants if
The dictionary must also contain an entry whose key is
Default
. The value of this
entry is a halftone dictionary to be used for any color component that does not
have an entry of its own.
When a halftone dictionary of some other type appears as the value of an entry in
a type 5 halftone dictionary, it applies only to the single colorant or color com-
ponent named by that entry’s key. This is in contrast to such a dictionary’s being
used as the current halftone parameter in the graphics state, which applies to all
color components. If nonprimary colorants are requested when the current half-
tone is defined by any means other than a type 5 halftone dictionary, the gray
halftone screen and transfer function are used for all such colorants.
nents for a
CMYK
device. In this example, the halftone dictionaries for the color
components and for the default all use the same spot function.
Example 6.2
27 0 obj
<< /Type /Halftone
/HalftoneType 5
/Cyan 31 0 R
/Magenta 32 0 R
/Yellow 33 0 R
/Black 34 0 R
/Default 35 0 R
>>
endobj