Postscript / Pdf Colour Architecture - Océ imagePRESS C7010VPS series Technical Manual

PostScript / PDF colour architecture

PostScript / PDF colour architecture
Introduction
This chapter describes the colour management of the PRISMAsync 2.2.
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 modes and templates
• Setting the defaults for the colour settings
• Spot colour table editing
• Administration of the pool of profiles and media families
• Media catalogue management
• Colour configuration management (import/export)
Click the following pdf for an overview how release 2.2 of the PRISMAsync controller handles
files:
.
Colour Management Module
A CMM (Colour Management Module) is used to convert colours from one colour space to
another colour space. The CMM used in the PRISMAsync controller 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.
Rendering intents
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.
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.
CIE-Based Colour Spaces
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:
118 Chapter 7 - Colour management
imagePRESS C7010VPS series v2.2