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Contradiction with techniques F73 & G182

From: <noreply@w3.org>
Date: Fri, 23 Nov 2012 03:03:44 +0000
Message-Id: <E1TbjYO-0003ZW-KL@tibor.w3.org>
To: public-comments-wcag20@w3.org
Name: Steven
Email: steven.miller@finance.gov.au
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):

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
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

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 

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 

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.


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.
Received on Friday, 23 November 2012 03:03:49 UTC

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