Edit comment LC-1235 for Accessibility Guidelines Working Group

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Comment LC-1235

Comment Shortname:

Commenter: Kiyochika Nakamura <nakamura-kiyochika@mitsue.co.jp> on behalf of Mitsue-Links Co., Ltd.

Message-id:

Section of the document concerned:

[Free text description]Document as a wholeIntroduction Related Documents Authoring tools The Role of User Agents The Four Principles of Accessibility Important New Terms Used in WCAG 2.0 Conformance Technology assumptions and the "baseline" Conformance levels and the baseline Conformance claims Content that conforms to WCAG 1.0 How to refer to WCAG 2.0 from other documents Guideline 1.1 Success Criterion 1.1.1 Guideline 1.2 Success Criterion 1.2.1 Success Criterion 1.2.2 Success Criterion 1.2.3 Success Criterion 1.2.4 Success Criterion 1.2.5 Success Criterion 1.2.6 Success Criterion 1.2.7 Guideline 1.3 Success Criterion 1.3.1 Success Criterion 1.3.2 Success Criterion 1.3.3 Success Criterion 1.3.4 Success Criterion 1.3.5 Guideline 1.4 Success Criterion 1.4.1 Success Criterion 1.4.2 Success Criterion 1.4.3 Success Criterion 1.4.4 Guideline 2.1 Success Criterion 2.1.1 Success Criterion 2.1.2 Guideline 2.2 Success Criterion 2.2.1 Success Criterion 2.2.2 Success Criterion 2.2.3 Success Criterion 2.2.4 Success Criterion 2.2.5 Success Criterion 2.2.6 Guideline 2.3 Success Criterion 2.3.1 Success Criterion 2.3.2 Guideline 2.4 Success Criterion 2.4.1 Success Criterion 2.4.2 Success Criterion 2.4.3 Success Criterion 2.4.4 Success Criterion 2.4.5 Success Criterion 2.4.6 Success Criterion 2.4.7 Success Criterion 2.4.8 Guideline 2.5 Success Criterion 2.5.1 Success Criterion 2.5.2 Success Criterion 2.5.3 Success Criterion 2.5.4 Guideline 3.1 Success Criterion 3.1.1 Success Criterion 3.1.2 Success Criterion 3.1.3 Success Criterion 3.1.4 Success Criterion 3.1.5 Success Criterion 3.1.6 Guideline 3.2 Success Criterion 3.2.1 Success Criterion 3.2.2 Success Criterion 3.2.3 Success Criterion 3.2.4 Success Criterion 3.2.5 Guideline 4.1 Success Criterion 4.1.1 Success Criterion 4.1.2 Guideline 4.2 Success Criterion 4.2.1 Success Criterion 4.2.2 Success Criterion 4.2.3 Success Criterion 4.2.4 Appendix A: Glossary Appendix B: Checklist Appendix C: Acknowledgements Appendix D: Comparison of WCAG 1.0 checkpoints to WCAG 2.0 Appendix E: References
or

Refinement of the section concerned:

Status:

open proposal pending resolved_yes resolved_no resolved_partial other assigned to Nobody Abma, Jake Abou-Zahra, Shadi Allan, Jim Auclair, Christopher Avila, Jonathan Babinszki, Tom Bailey, Bruce Bernard, Renaldo Bernier, Alex Blake, Matthew Boudreau, Denis Brewer, Judy Butler, Shari Campbell, Alastair Carlson, Laura Chakravarthula, Srinivasu Cirrincione, Pietro Conway, Vivienne Cooper, Michael Crutchfield, Elizabeth Deltour, Romain Dick, Wayne Ding, Chaohai Dirks, Kim Dixit, Shwetank Draffan, E.A. Duggin, Alistair Eggert, Eric Elledge, Michael Faulkner, Steve Ferraz, Reinaldo Fiers, Wilco Fischer, Detlev Foliot, John Garrish, Matt Garrison, Alistair Gower, Michael Guarino Reid, Loretta Hakkinen, Markku Haritos-Shea, Katie Henry, Shawn Hoffmann, Thomas Horton, Sarah Isager, Kasper Jensen, Tobias Christian Johansson, Stefan Johlic, Marc Johnson, Rick Jones, Crystal Joys Andersen, Wilhelm Kapoor, Shilpi Keim, Oliver Kirkpatrick, Andrew Kirkwood, John Kiss, Jason Kraft, Maureen Ku, JaEun Kurapati, Sujasree Lauke, Patrick Lauriat, Shawn Lee, Steve Lemon, Gez Li, Alex Li, Kepeng Li, Liangcheng Loiselle, Chris Lowney, Greg Lui, Edwina Lund, Adam Ma, Jia MacDonald, David Mace, Amanda Manser, Erich Martin, Debra McCormack, Scott McMeeking, Chris McSorley, Jan Milliken, Neil Montgomery, Rachael Mueller, Mary Jo nicole, windmann Niemann, Gundula Nurthen, James O Connor, Joshue Oh, Jeong-Hun Panchang, Sailesh Pandhi, Charu Pasi, Aparna Patch, Kimberly Philipp, Melanie Pluke, Mike Pouncey, Ian Repsher, Stephen Rochford, John Runyan, Marla Savva, Andreas Sawczyn, Steve Schnabel, Stefan Seeman-Kestenbaum, Lisa Sims, Glenda Singh, Avneesh Skotkjerra, Stein Erik Sloan, David Smith, Alan Smith, Jim Solomon, Adam Spellman, Jeanne F Strobbe, Christophe Suprock, Greg Swallow, David Thompson, Kenneth Thyme, Anne Ueki, Makoto Vaishnav, Jatin Vanderheiden, Gregg Venkata, Manoj Wahlbin, Kathleen Wang, Can WANG, WEI White, Jason Zelmanowicz, Erica Zerner, Adam Zhang, Mengni

Type: substantive editorial typo question general comment undefined

Resolution status:

Response drafted Resolution implemented Reply sent to commenter

Response status:

No response from Commenter yet Commenter approved disposition Commenter objected to disposition
Commenter's response (URI):

Comment:

Comment: Is there any scientific or other basis for a luminosity contrast ratio method? Also, is there any reason to choose 5:1 and 10:1? I understand that a reference value is needed for these criteria because it should be testable, but if there is no basis, how can we rely on it?

Proposed Change:

Add a link to the document which explains why 5:1 and 10:1 LCR ratio are sufficient if there is such a document. Otherwise, explain why the WG has decided to choose 5:1 and 10:1.

Related issues: (space separated ids)

WG Notes: [TEAMA] Discussed in the 08 March 2007 telecon: accepted by unanimous consent http://www.w3.org/WAI/GL/2007/03/08-wai-wcag-minutes.html Response: http://lists.w3.org/Archives/Public/public-comments-wcag20/2007Jun/0064.html

Resolution: The 5:1 contrast ratio provides a minimum contrast of around 3:1 for the major types of color blindness. A contrast ratio of 3:1 is the minimum level recommended by ANSI/HFS 100-1988. 10:1 provides approximately 7:1 contrast ratio for individuals with color blindness, which is the recommended contrast level in ANSI/HFS 100-1988. We have added the following to the Intent sections of SC 1.4.1 and 1.4.4: The 5:1 contrast ratio provides a minimum contrast of around 3:1 for the major types of color blindness. A contrast ratio of 3:1 is the minimum level recommended by [ISO-9241-3] and [ANSI-HFES-100-1988]. Calculations in ISO 9241-3 and ANSI/HFS 100-1988 are for body text. A relaxed contrast ratio is provided for text that is much larger (twice as tall and with three time the thickness of lines in the character). Notes on formula Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [IEC-4WD] and on "A Standard Default Color Space for the Internet - sRGB" [sRGB]. The formula (L1/L2) for contrast is based on ISO 9241-3 and ANSI/HFS 100-1988 standards. The ANSI/HFS 100-1988 standard calls for the contribution from ambient light to be included in the calculation of L1 and L2. The .05 value used is based on Typical Viewing Flare from IEC/4WD 61966-2-1 and the sRGB paper by M. Stokes et al. This success criterion and its definitions uses the terms contrast ratio and relative luminance rather than luminance to reflect the fact that Web content does not emit light itself. The contrast ratio gives a measure of the relative luminance that would result when displayed. (Because it is a ratio, it is dimensionless.) Note: Refer to related resources for a list of tools that utilize the contrast ratio to analyze the contrast of Web content.

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