The International Organization for Standardization (ISO) has announced the completion of the development of ISO 20677, Image technology colour management — Extensions to architecture, profile format, and data structure. The ISO Technical Committee 130, Joint Working Group 7 (TC130/JWG7) that developed this international standard works closely with the International Colour Consortium (ICC) on standards focused on colour management.
The Association for PRINT Technologies (APTech) administers TC130 JWG7 and coordinates the activities of the U.S.-based representatives that are members of this group. In addition, APTech acts as Secretariat for the ICC, the acknowledged leader in colour management.
While the current architecture has worked well and meets most user requirements, new potential applications are emerging, and tomorrow’s colour communication requires a more flexible and extensible system. ISO 20677 addresses these new requirements.
This international standard describes an expanded profile specification, with profile connections that permit greater flexibility and functionality. Central to the new architecture is a move from a fixed profile connection space based on D50 Colourimetry, towards a much more flexible PCS definition, including support for any illuminant, any colourimetric observer and any number of PCS channels – enabling both spectral and multiplex PCS connections. Additionally, minimum structural and operational requirements for writing and reading ICC profiles are defined.
“ICC Color Management systems have been reliable work horses behind colour reproduction systems in the graphic arts,” says Dr. Max Derhak, ICC Co-Chair, Chair of the ICC Architecture Working Group and Principal Colour Scientist at Onyx Graphics. “As a colour technologies developer, I realized long ago that there are limitations to what can be done with ICC colour profiles. Therefore, I have endeavoured to provide leadership in pioneering new approaches and technologies that have become part of iccMAX.”
Value added through using ISO 20677 within business process resides in functionality, connectivity, and computational efficiency. A wide range of functionality can be implemented through the much richer set of processing elements and connection spaces. The framework for implementation is provided license-free in an open-source reference implementation (RefIccMax), significantly reducing the cost of implementing the new transform functionality. The ability to convert between binary and XML representations of the profile, and to call text data files at profile creation time, also simplifies the profile-generation process. A further enhancement is the ability to provide run-time input to a transform using environment variables. Using these features, end users will be able to perform a range of tasks that were not previously possible without specialist or custom software.
ISO 20677 preserves the core ICC concept of a well-defined connection space for profiles, while simultaneously supporting connection to compatible iccMAX profiles using highly flexible connection spaces, and legacy v2 and v2 ICC profiles. Developers can focus their effort on the specific element of the workflow that adds value to their product, without the need to build a complete transform pipeline from original to preview and output. End users will see a more seamless connection between different elements of their workflow, especially where those elements require processing not supported in ICC v4.
The use of functionally encoded transforms carries a potential run-time computation cost, though the extended function set provides wider opportunities for optimization. Developers can choose which features to use; those that reduce profile size (e.g., lossless compression of elements, sparse matrices, transforms by reference, enabling local caching of selected transforms) and subsequent costs of network transmission and storage; or features that optimize computational efficiency.
Implementors can eliminate the need for large libraries of profiles and the problem of profile selection by providing a single profile for a range of conditions, which is configured at run-time. In addition to the greater flexibility, end users should see an overall reduction in computation time and communication bandwidth as software providers are able to match requirements more directly with a wider range of processing elements.
