This chapter describes the colour management of the PRISMAsync Print Server.
NOTE
For a description of the colour management in IPDS mode, see chapter "Colour management in IPDS mode" in "SRA IPDS".
Machine related settings and system level default settings and colour settings can be found in the PRISMAsync Settings Editor. The system level colour settings include:
Colour presets
Setting the defaults for the colour settings
Spot colour table editing and colour mapping
Colour and information bars
Administration of input profiles
Administration of output profiles and media families
Media catalogue management
Colour configuration management (import/export)
Enable G7 profiling and calibrations
A CMM (Colour Management Module) is used to convert colours from one colour space to another colour space. The CMM used in the PRISMAsync Print Server is the Adobe ACE CMM.
To improve performance of colour management for complex pages, a fast Device Link interpolation is developed, which runs on the Graphics Processing Unit (GPU) of a graphics card. ACE is used to calculate the values that go into the Device Link. With the Device Link, the colour management on the GPU considerably is faster than with ACE on a processor.
In both DeviceRGB and DeviceCMYK it is possible to use different rendering intents.
Absolute colorimetric
Relative colorimetric
Perceptual
Saturation
The saturation intent for DeviceRGB applies a hue rotation in the gamut mapping to map the pure RGB colours to the pure printer colours. This default behaviour can be switched off.
If the saturation rendering intent is used in a normal way in CMYK, the pure CMY colours are not mapped to the pure output colours. By using a Device Link in the CMM these pure colours are correctly mapped. So 100% cyan will be printed as 100% cyan and RGB grey or black with black toner. This default behaviour can be switched off.
Colour defined in CIE-based colour spaces are also called device-independent colours. These are colours that have an input profile attached in the form of a PostScript Colour Space Array (CSA) that is also defined in the job.
There are several CIEBased colour spaces:
CIEBasedA
A colour space with 1 input value per colour, e.g. for grayscales.
CIEBasedABC and CIEBasedDEF
Colour spaces with 3 input values per colour (e.g. RGB-like colour spaces, Lab or XYZ). CIEBasedABC are simple matrix-based colour spaces while CIEBasedDEF allow for a 3D interpolation table.
CIEBasedDEFG
Colour spaces with 4 input values per colour (e.g. CMYK colour spaces).
The PRISMAsync Print Server is shipped with a number of output profiles for the standard media families. The PRISMAsync embedded profiler can automatically create and register output profiles for a (new) media family.
Spot colour tables that are supported are:
PANTONE® Goe™ coated, PANTONE® Goe™ uncoated, PANTONE+® solid coated, PANTONE+® solid uncoated, HKS K, HKS K 3000+, HKS N, HKS N 3000+.
PANTONE® with suffix CVC, CHC, CVP, CVS, CH, CS, PC, EC will be printed using C suffix. PANTONE® with suffix CVU, CHU will be printed using U suffix.
Also colour names like PMS 185 are supported and will be mapped to PANTONE® 185 solid coated.
The Settings Editor provides functionality to add tint values for any given (custom) spot colour. Adding a tint value to one of the pre-installed spot colours always results in a new custom colour with the same name.
Using the PRISMAsync Settings Editor, a user can export and import the entire colour configuration of the print server at once. It is not possible to export individual colour configuration items like profiles.