ICC Workflow Working Group
Color Management for Distributed Systems
Requirements Document
Color Management Requirements Subproject
Version 0.10 - 12 July 2004
Subproject: Color Management Requirements Subproject
URL: http://wb.color.org:8080/~icc/login
Synopsis: Identify and document fundamental requirements for distributed systems color management, with an emphasis on color management requirements for the Graphic Arts industry.
Color management is defined as:
color management (digital imaging) is the communication of the associated data required for unambiguous interpretation of color content data, and application of color data conversions as required to produce the intended reproductions.
Note 1: Color content may consist of text, line art, graphics, and pictorial images, in raster or vector form, all of which may be color managed.
Note 2: Color management considers the characteristics of input and output devices in determining color data conversions for these devices.
Requirements Table Field Descriptions:
Id: Reference for the requirement to uniquely identify it. Should not be changed or reused.
Requirement: This is the actual requirement of the industry, as the authors and reviewers understand it.
Source: The name of the particular industry source. Each entry should begin with either GA: , DigCin:, DigPhot:, Office: , or All: -- to indicate which industry is most interested in the requirement.
Any external source document or contact information might be mentioned here, including: name, designation, telephone number and email address. The GASIG Graphic Arts Problem List is referenced as a source as GA:Users. This information came from user surveys conducted by the ICC in Europe and the US, and then reviewed with:
· GATF color management conference users (Priorities assigned by consolidating input from over 100 graphic arts professionals at December 2002 GATF Color Conference. --from Larry Warter of The Fuji Photo Group)
· Quebecor World
· Global Graphics Software
· Oak Technology
· CGS Publishing Technologies International, Germany
· Integrated Color Solutions, Inc
· Adobe Systems Limited
Response: How the ICC plans to or has responded to the requirement.
Status: This is the state of the requirement. Terms to use here include: ‘In V4’, ‘Refer to XXX,’ ‘In GASIG White Paper’, ‘In Development’, ‘Deferred’, and ‘Under Review’.
Notes: Any information on the requirement that the project feels important. This might relate to the change history of the individual requirement (e.g., the date the requirement came in or was approved, when a requirement was deemed satisfied, who is doing implementation, etc.).
Use Stories (actual testable example – necessary but not sufficient):
Use cases:
Re-purposing from a described color-rendered color content to a destination optimization in which the conversion is specified by the originator
Re-purposing from a described color-rendered original (color content) to deferred representation
Re-targeting from a described visualization to an nth visualization
Original purposing at the source (the user downloads the raw image from the their digital camera and color-renders it for a particular visualization)
Original purposing deferred to a remote destination
Requirements Tables:
Table 1. Function Requirements
§ Functions performed: The inputs and outputs of a color management system and the computations to be performed under the normal range of inputs. In addition to text description, there are numerous representational forms such as mathematical formulae, flow charts, block diagrams, tables, formal grammars, graphs, plots etc. that can be used to facilitate this specification.
§ Structure: Particular architectural constraints on the subsystems, modules, functions, subroutines or other structural aspect of the system design. Where structure is constrained, the relevant interface constraints must be specified as appropriate.
Industry / CM Specifications /Id / Function Requirements / Source / Response / Status / Notes /
1. / Utilize associated data required for unambiguous interpretation of color content data, and apply color data conversions, i.e., color-rendering algorithms, as required to produce intended (per application use case) reproductions. / ICC Historical / InV4
2.
3. / Re-targeting capability
4. / Re-purposing capability
5. / Re-purposing
6. / Re-purposing with embedded transform directive
7. / Incorporate color appearance adaptation.
8. / Incorporate gamut mapping.
9. / Incorporate device colorant channel allocation.
10. / Allow for simultaneous co-optimization of color-appearance adaptation, source(image) -to-destination(device) preference color rendering, source(image) -to-destination(device) gamut mapping(fitting), and destination device colorant channel allocation. / ICC Historical / InV4 / Gamut-mapping here refers to fitting the colorimetric colors from an original that fall outside of the destination gamut.
11. / During color-rendering, allow for both
a) direct gamut mapping between source and destination gamuts, and b) the use of an intermediate gamut as a target-device-independent color-rendering reference. / ICC Historical / InV4, and standardization of the intermediate gamut is underway. / a) can be accomplished by a CMM using the ICC media-relative colorimetric intent data in the source and destination profiles.
b) can be accomplished either by a CMM as in a) or by a profile builder.
12. / During color-rendering, allow for specific control of initial colorant mapping – trading off physical colorant attributes (e.g., GCR/UCR, primary colorant purity, Ink Limit) against preferred color reproduction. / GA:Users
13. / Re-color-render color encoded data that has been prepared for display via one system in one viewing environment so that it is prepared for colorimetrically equivalent (within gamut limitations) display via a second system and/or in a second viewing environment. This is called re-targeting. / ICC Historical
14. / During re-color-rendering, allow for specific control of colorant re-mapping – trading off physical colorant attributes (e.g., GCR/UCR, primary colorant purity, Ink Limit) against colorimetric or color appearance matching. / GA:Users / ICC DeviceLink profiles
15. / Re-color-render color encoded data that has been prepared for display via one system so that it is specifically optimized for display via a second system and/or in a second viewing environment. This is called re-purposing. / ICC Historical
16. / Color manage color content consisting of text, line art, graphics, and pictorial images, in raster or vector form, such that equal source colors can be color-rendered to equal destination colors, independent of color content data type. / ICC Historical
17. / Color manage color content consisting of text, line art, graphics, and pictorial images, in raster or vector form, such that color-rendering can be selectively controlled for each color content data type. / GA:Users
18. / Allow for selection and execution of well-known, consistent, color-rendering behaviors. A minimum set of well-known color-rendering behaviors is:
a) Media-relative colorimetric
b) Absolute colorimetric
c) Media-relative colorimetric with black point compensation / GA:Users
19. / Allow for preferred and/or customized color-rendering behaviors. / GA:Users
DigPhot
20. / Specify color-rendering behaviors such that consistent algorithms can be implemented across a plurality of color management environments and computer operating systems. / GA:Users
DigCin
Table 2. Interface Requirements
§ Interface specification: A complete, detailed specification of the external interface defined for a color management system. This should contain the form of access, data conventions for inputs and outputs, limits on parameters, conventions for checks to be performed to validate inputs. If the system connects to other systems including libraries, operating systems, language run-time packages, or other external software, include a complete interface specification as above.
§ Exception treatment: A complete description of operation of the color management system under illegal/unspecified/undefined conditions or other exceptional external conditions and the required actions. If some conditions are assumed to be always met, these assumptions should be made clear if possible. If the action under some set of conditions is unspecified, it is better to state the condition and specify the actions as “unspecified”.
Industry / CM Specifications /Id / Interface Requirements / Source / Response / Status / Notes /
21. / Consider the characteristics of input and output devices in determining color data conversions for these devices. / GA:Users
22. / Characterize capture devices’ input gamut – as a function of media (if scanner), light source (if scanner), viewing environment (if camera) and sensor spectral sensitivity. / ICC Historical
23. / Characterize print devices’ output gamut as a function of media, intended viewing environment, colorant set, colorant laydown strategy (e.g., halftone). / ICC Historical
24. / Encode, format, and associate data required for unambiguous interpretation of color content data, such that the associated data can be communicated and associated with the color content data across a plurality of color management environments and computer operating systems. / GA:Users
25. / Encode, format and associate data required for unambiguous indentification and/or specification of an intended color-rendered reproduction (e.g., PDF/X Output Intent) of color content data, such that the associated data can be communicated and associated with the color content data across a plurality of color management environments and computer operating systems. / GA:Users
26. / Encode, format, and associate data required for unambiguous re-color-rendering from an unambiguously identified source color content data to a specified reproduction, allowing for specific control of colorant re-mapping, such that the associated data can be communicated and associated with the color content data across a plurality of color management environments and computer operating systems. / GA:Users / ICC DeviceLink profiles / Note that current ICC implementations may not be cross-vendor compatible and the ICC V4 upgrade will address that.
27.
28.
29.
Table 3. Legal Encumbrance Requirements
Ownership of the elements of color management systems; costs for use; licenses and use of licensed products built in compliance with the specified color management system; restrictions on accessibility to the color management system, on use, on publication of concepts and details.
Industry / CM Specifications /Id / Legal Requirements / Source / Response / Status / Notes /
30. / Insert IP agreement
31.
32.
33.
34.
35.
Table 4. Performance Requirements
Restrictions on memory usage, speed of execution, speed of communications, or other quantifiable performance measurements that may be stated as limits, averages, or in relation to other external measurables.
Industry / CM Specifications /Id / Performance Requirements / Source / Response / Status / Notes /
36. / Performance is deliberately assigned as an attribute of individual vendor implementations. / Historical ICC / new
37. / Specifications shall be such that implementation performance can be scaled in proportion to industry segment/customer color quality requirements. / Historical ICC / new
38.
39.
40.
41.
Table 5. Reliability Requirements
Expected failure rate of the color management system, expected actions when failures occur, percentages of failures that will cause additional problems.
Industry / CM Specifications /Id / Reliability Requirements / Source / Response / Status / Notes /
42. / Specifications allow for precision and accuracy such that colors from a source appearance environment and encoding can be color-rendered to a destination appearance environment and encoding within error tolerance +/- 2 deltaE2000 when those colors are inside or on the boundary of the destination color gamut. / Historical ICC / Specified for ICC media-relative colorimetric intent in V4.
43.
44.
45.
46.
47.
Table 6. Standards Compliance Requirements
Applicable standards to which parts or all of a color management system must comply. Compatibility with external standards or industry trends is required. Give specifics where possible and include references to other documents where possible.
Industry / CM Specifications /Id / Standards Requirements / Source / Response / Status / Notes /
48. / ISO, CIE / PDF/X
49.
50.
51.
52.
53.
Table 7. System Environment Requirements
Required programming language usage, specific compiler compatibilities, other programming restrictions, operating system compatibility, machine and configuration restrictions.
Industry / CM Specifications /Id / Environment Requirements / Source / Response / Status / Notes /
54. / Specifications and implementations are publicly defined such that the required precision and accuracy can be achieved across single- and multi-vendor color management implementations utilizing a plurality of computer operating systems. / Historical ICC / Specified for ICC media-relative colorimetric intent in V4.
55. / Identify data encodings and formatting structures such that data required for unambiguous interpretation of color content data, can be associated in a persistent manner with specific color content data, across a plurality of color management environments and computer operating systems. / GA:Users
56. / Identify data encodings and formatting structures such data required for unambiguous indentification and/or specification of an intended color-rendered reproduction can be associated in a persistent manner with specific color content data, across a plurality of color management environments and computer operating systems. / GA:Users
57. / Specify data associated with color content data such that the reproduction condition of the color content data is persistently unambiguous across a plurality of color management environments and computer operating systems. / GA:Users
58.
59.
Table 8. Tools and Installation Requirements
Software or other tools to be supplied for the installation, use, and/or maintenance of the color management system.
Industry / CM Specifications /Id / Tools Requirements / Source / Response / Status / Notes /
60. / Color management systems behaviors and interfaces shall be specified such that software and tools comprising a color management system from any specific vendor can perform consistently when implemented for a plurality of computer operating systems. / GA:Users
61.
62.
63.
64.
65.
Table 9. Training Requirements
The customer’s training requirements. What knowledge is required to install, use and maintain the color management system? What supporting documents might be required? Will the developers be required to participate in training?
Industry / CM Specifications /Id / Training Requirements / Source / Response / Status / Notes /
66. / Color management systems behaviors shall be specified such that users can be trained in color management theory and workflow applications independent of any particular computer operating system. / GA:Users
67.
68.
69.
70.
71.
Table 10. User Presentation Requirements
Particular terminology, prompts, desired appearance, ease of use, or usability aspects that constrain the design. This may include the requirement for particular operational sequences or timing of user perceived events.