ICC Issues Major Revision to Reduce Ambiguity and Enhance Interoperability
Press release from the issuing company
March 13, 2002 -- The International Color Consortium has issued a major revision of its specification, chiefly designed to eliminate ambiguities that have led to concerns about output consistency and interoperability of different profiles and Color Management Modules.
“The previous specification has been widely adopted by the color imaging community and proved very important in achieving and maintaining color fidelity of images,” noted ICC Technical Secretary Tony Johnson of the London College of Printing. “This widespread use has also identified ways in which the spec can be even further improved.”
Specifically, ambiguities in the previous version of the specification could, in some circumstances, allow producers of color profiles for specific devices to interpret the reference space differently. Thus, some color profiles from different vendors could be inconsistent, and some Color Management Modules could interpret the same or similar profiles in different ways.
“The changes in the new version of the specification are designed to ensure that profile builders understand the reference color space precisely, and exactly what is required of the profile,” Johnson said.
The new revision of the ICC spec was made available last December for a period of review and comment by interested parties. It was finalized by ICC following conclusion of that review period in early February.
Specific changes in the specification include:
For perceptual rendering, the dynamic range of the PCS and the assumed level of illumination for viewing have been identified.
Chromatic adaptation information is now required if the actual illumination source is not D50. When data is intended for viewing in illumination conditions differing from those of ISO 3664, the transformation required for correction of the data must be specified. This change is expected to be especially important for color monitor profiles.
Where profiles involve more than the usual CMYK colorants, the additional colors can now be specified by their XYZ or L*a*b* coordinates, and the sequence of printing can also be specified.
New look-up table specifications have been provided, and additional clarifications have been made concerning such issues as rendering intents, definition of tags for three-component devices, and content and structure of monochrome profiles.
“This revision does not mean that ICC sees its work as complete,” Johnson said. “There are important issues still to address. Many users would like to see the ICC ensure conformance of profiles and CMMs to the specification. Others have workflow needs that cannot easily be met with the existing architecture.” ICC is working on approaches to these remaining issues, Johnson said.
The new revision, he added, aims to ensure improved consistency of results when using ICC Profiles, while still retaining the flexibility to let users produce profiles that best suit their requirements.
The new spec, designated ICC.1:2001-12, Format for Color Profiles, is available for free download from the ICC website, www.color.org.
The International Color Consortium was established in 1993 by eight industry vendors for the purpose of creating, promoting and encouraging the standardization and evolution of an open, vendor-neutral, cross-platform color management system architecture and components. The outcome of this cooperation was development of the ICC profile specification, now in use by leading vendors of color management
ICC now has more than 60 members. NPES The Association for Suppliers of Printing, Publishing and Converting Technologies serves as administrative secretariat.
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