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Re: Contradiction with techniques F73 & G182

From: Loretta Guarino Reid <lorettaguarino@google.com>
Date: Thu, 7 Mar 2013 18:05:42 -0800
Message-ID: <CAHu5OWbbcQkaD-sDPNY8XZ5J1BtkZnb36HQV-iFDRCW=10FiSA@mail.gmail.com>
To: steven.miller@finance.gov.au
Cc: public-comments-wcag20@w3.org
On Thu, Nov 22, 2012 at 7:03 PM, <noreply@w3.org> wrote:

> Name: Steven
> Email: steven.miller@finance.gov.au
> Affiliation:
> Document: TD
> Item Number: G183
> Part of Item: Applicability
> Comment Type: general comment
> Summary of Issue: Contradiction with techniques F73 & G182
> Comment (Including rationale for any proposed change):
> Greetings,
>
> I am hoping to resolve an inconsistency in WCAG 2.0 techniques for WCAG
> conformance of Criterion 1.4.1, where there is a direct contradiction
> between techniques F73 & G182, and G183.
>
> F73: Failure of Success Criterion 1.4.1 due to creating links that are not
> visually evident without color vision
>
> Failure technique F73, clearly states “If the non-colour cue only happens
> when the mouse hovers over the link or when the link receives focus, it is
> still a failure”
>
> The test then confirms this by stating
> Procedure
> 1.      Check that each link within text that is part of a sentence or
> paragraph (or other area where they could be mistaken as non-linked text)
> in the page is underlined or otherwise visually identifiable (i.e., bolded,
> italicized) as a link without relying on color (hue).
>
> Expected Results
> •       If check #1 is false, then this failure condition applies and the
> content fails this Success Criterion.
>
> I think the key terminology of the test being “visually identifiable” –
> this would exclude mouseover’s, hover, or on focus, which would all require
> some form of interaction to make the link visually identifiable.  Of course
> it could be argued that by interacting with the link “mouseover’s”,
> “keyboard focus”, etc, would then become visually identifiable and
> therefore passes the test.  I would suggest updating the test with:
>
> .....   otherwise visually identifiable (i.e., bolded, italicized) as a
> link without relying on color (hue) or preceding interaction such as
> “hover” or “keyboard focus”.
>
> This technique is supported by G182 and accepted through recent discussion
> on the WAI-IG mailing list (November 2012) at
> http://lists.w3.org/Archives/Public/w3c-wai-ig/2012OctDec/subject.html
>
> G182: Ensuring that additional visual cues are available when text color
> differences are used to convey information
>
> Sufficient technique G182, which states “The intent of this technique is
> to provide a redundant visual cue for users who may not be able to discern
> a difference in text colour”
>
> Though the use of the word “redundant” muddy’s the meaning of the
> sentence, it seems obvious that the intent is meant to provide an
> additional (or complementary) visual cue for users who cannot identify a
> link visually.
>
> The test confirms this interpretation by stating
>
> Procedure
> 1.      Locate all instances where the color of text is used to convey
> information.
> 2.      Check that any text where color is used to convey information is
> also styled or uses a font that makes it visually distinct from other text
> around it.
>
> Expected Results
> •       Check #2 is true.
>
> The key terminology this times is “makes it visually distinct from other
> text around it”, this would again exclude mouse over’s, hover, or on focus
> which are not visually distinct from other text around it.  Like F73 some
> form of interaction is required to make “hover”, etc, visually distinct.
>
> Unfortunately these techniques are contradicted by G183.
>
> G183: Using a contrast ratio of 3:1 with surrounding text and providing
> additional visual cues on focus for links or controls where color alone is
> used to identify them
>
> Sufficient Technique: G183 provides for “a relative luminance (lightness)
> difference of 3:1 or greater with the text around it can be used if
> additional visual confirmation is available when a user points or tabs to
> the link”
>
> The test confirms this point by allowing
>
> Procedure
> 1.      Locate all instances where color alone is used to convey
> information about text.
> 2.      Check that the relative luminance of the color of the text differs
> from the relative luminance of the surrounding text by a contrast ratio of
> at least 3:1.
> 3.      Check that pointing (mouseover) to the link causes a visual
> enhancement (such as an underline, font change, etc.)
> 4.      Check that moving keyboard focus to the link causes a visual
> enhancement (such as an underline, font change, etc.)
>
> Expected Results
> •       Checks #2, #3, and #4 are all true.
>
> Points 3 and 4 of the procedure clearly allows for the use of “mouseover”
> or “keyboard focus” for links that are otherwise identifiable by color
> alone (providing in meets minimum contrast ratios with surrounding text).
>
> This technique is identified as applying to Success Criterion 1.4.1.
>
> SC1.4.1: Use of Color
>
> The principal of Success Criterion 1.4.1 provides for users to be able to
> access information that is conveyed by color.  The criterion alludes to
> this further by indicating “providing the information conveyed with color
> through another visual means ensures users who cannot see color can still
> perceive the information”.
>
> I believe the intent of this criterion is to ensure that all users can
> perceive any information presented on screen programmatically or visually
> (without interaction).  Otherwise many color impaired users will need to
> interact with all the content of every page to determine whether or not
> there is information conveyed that they are unaware of.
>
> Note: In the case of links it is difficult to hover over the link text, to
> determine whether it is the link text, when you don’t first recognize it as
> the link text!
>
> Also strong consideration needs to be given to the use of tablets and
> smart phones, where many users are now using this as their preferred (or
> only) option to accessing online information.  Mouseover or "On focus" does
> not allow these users to identify links.  Furthermore these users are also
> more likely to be effected by environmental considerations such as glare,
> or poor ambient light.
>
> Recommendation
>
> In line with the intent of Success Criterion 1.4.1 (explained above), then
> it should be a reasonable expectation that sufficient technique G173 be
> removed or adjusted so that there is no contradiction with other techniques
> or the intent of the associated criteria.
>
> NOTE: Aside from being confusing for developers, as to which technique to
> apply when developing an accessible site; and in particular for claiming
> WCAG 2.0 conformance.  Many governments are now adopting WCAG 2.0 as a form
> of governance for web accessibility.  For Governance to be applied
> effectively, it is imperative that there are no contradictions in the
> definitions and measure of conformance (techniques); and preferably no
> ambiguity.
>
>
>
> Proposed Change:
> G173 be removed or adjusted so that there is no contradiction with
> techniques F73 & G182; or the intent of criterion 1.4.1.
>
> If the solution was to amended G173, then I would suggest that as a
> minimum, any references to mouseovers and "on focus" as an acceptable
> visual cue, be removed including in the test (procedure points 3 & 4).
> Noting that these options will not allow cater for the accessibility
> requirement on mobile devices.
>
> I also suggest that W3C look  at reviewing success criterion 1.4.1, so as
> to make reference to accessibility on mobile devices; when this process is
> next undertaken.
>
>
> ================================
Response from the Working Group
================================
Thank you -- we agree that these are confusing and need to be clarified.

Here is some background followed by the changes we are making to the
failure to fix this.

As discussed in the technique description, because G183 requires a relative
luminance (lightness) difference of 3:1 or greater with the text around it,
the link is visually identifiable by its contrast with the surrounding
text, not by its color( hue) difference. This is similar to SC 1.4.3, which
requires a minimum contrast ratio between text and its background. And when
this technique is used with links, the link hue is often the same as the
surrounding text, only darker.

However, since this technique applies only to links and other interactive
controls, the working group felt that additional feedback would be helpful
to confirm that the contrasting text is interactive, but that is was
acceptable for this additional feedback to be provided only on focus or
hover.

This technique is an edge case for what the working group felt was
acceptable for text, which is why the description includes the advice:
"While using this technique is sufficient to meet this success criteria, it
is not the preferred technique to differentiate link text."

NOTE:  Red and Pink are the same color (hue) but they have different
lightness (which is not color ).   So red and pink would pass the
requirement for "not distinguished by color (hue) alone" since they differ
by lightness (which is not color) - as long as the difference in lightness
(contrast) is 3:1 or greater.   (e.g. if surrounding text is RED and the
link is PINK it would pass.  Similarly a light green and a  dark red differ
BOTH by color AND by lightness so they would pass if the contrast
(lightness) difference is 3:1 or greater) before focus or pointing. )


To make this clearer we are:

A)  CHANGING THE "DESCRIPTION"  OF THE FAILURE TO THE FOLLOWING:


The objective of this failure is to avoid situations in which people who
cannot perceive color differences cannot identify links (when people with
color vision can identify links). Link underlines or some other non-color
visual distinction are required (when the links are discernible to those
with color vision).

While some links may be visually evident from page design and context, such
as navigational links, links within text are often visually understood only
from their own display attributes. Removing the underline and leaving only
the color difference for such links would be a failure because there would
be no other visual indication (besides color) that it is a link.

NOTE1 :  Red and Pink are the same color (hue) but they have different
lightness (which is not color ).   So red and pink would pass the
requirement for "not distinguished by color (hue) alone" since they differ
by lightness (which is not color) - as long as the difference in lightness
(contrast) is 3:1 or greater.   (e.g. if surrounding text is RED and the
link is PINK it would pass.  Similarly a light green and a dark red differ
BOTH by color AND by lightness so they would pass if the contrast
(lightness) difference is 3:1 or greater) before focus or pointing. )

Note 2:  There is no requirement that links be identifiable by people who
cannot perceive color if they are not perceivable for those with color
vision. (e.g. if the links are hidden for everyone – as in a game or test).

Note 3: If the non-color cue only happens when the mouse hovers over the
link or when the link receives focus, it is still a failure.

Note 4: If the link is a different color and bold it would not fail because
the boldness is not color dependent.


B) CHANGING THE TEST FOR THE FAILURE AS FOLLOWS;

1.    Check that each link in the page that is identifiable by color (hue)
is visually identifiable via some other means (e.g., underlined, bolded,
italicized, sufficient difference in lightness, etc).


C) ADDING THE FOLLOWING TWO TECHNIQUES TO "RELATED TECHNIQUES" SECTION
G182: Ensuring that additional visual cues are available when text color
differences are used to convey information
G183: Using a contrast ratio of 3:1 with surrounding text and providing
additional visual cues on focus for links or controls where color alone is
used to identify them



Loretta Guarino Reid, WCAG WG Co-Chair
Gregg Vanderheiden, WCAG WG Co-Chair
Michael Cooper, WCAG WG Staff Contact


On behalf of the WCAG Working Group
Received on Friday, 8 March 2013 02:06:12 GMT

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