Specifies the color space in which a color value is specified (for example, RGB or Grayscale).

Values:

IG_PDF_DEVICE_GRAY	Grayscale color specification. Requires 1 value entry to specify the color.
IG_PDF_DEVICE_RGB	Red-Green-Blue color specification. Requires 3 value entries to specify the color.
IG_PDF_DEVICE_CMYK	Cyan-Magenta-Yellow-Black color specification. Requires 4 value entries to specify the color.