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                                             270
CHAPTER 4                                                                Graphics



A DeviceN color space is specified as follows:
     [ /DeviceN names alternateSpace tintTransform ]

or
     [ /DeviceN names alternateSpace tintTransform attributes ]

It is a four- or five-element array whose first element is the color space family
name DeviceN. The remaining elements are parameters that a DeviceN color
space requires.

The names parameter is an array of name objects specifying the individual color
components. The length of the array determines the number of components in
the DeviceN color space, which is subject to an implementation limit; see Appen-
dix C.The component names must all be different from one another, except for
the name None, which can be repeated as described later in this section. (The
special name All, used by Separation color spaces, is not allowed.)

Color values are tint components in the range 0.0 to 1.0:

• For DeviceN color spaces that do not have a subtype of NChannel, 0.0 always
  represents the minimum amount of colorant; 1.0 represents the maximum.
  Tints are always treated as subtractive colors, even if the device produces out-
  put for the designated component by an additive method. Thus, a tint value of
  0.0 denotes the lightest color that can be achieved with the given colorant, and
  1.0 the darkest. (This convention is the same one as for DeviceCMYK color
  components but opposite to the one for DeviceGray and DeviceRGB.)
• For NChannel color spaces, values for additive process colors (such as RGB) are
  specified in their natural form, where 1.0 represents maximum intensity of col-
  or.

When this space is set to the current color space (using the CS or cs operators),
each component is given an initial value of 1.0. The SCN and scn operators re-
spectively set the current stroking and nonstroking color. Operand values sup-
plied to SCN or scn are interpreted as color component values in the order in
which the colors are given in the names array, as are the values in a sampled im-
age that uses a DeviceN color space.

The alternateSpace parameter is an array or name object that can be any device or
CIE-based color space but not another special color space (Pattern, Indexed,
Separation, or DeviceN). When the color space is set to a DeviceN space, if any of

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