RE: Understanding of SC 1.4.11

  *   We only care about the contrast with the outside of any boundary of the UI component when meeting the first bullet of the SC. The issue here is that if

Thanks for your response Mike.  Take the following example:
A dark blue page background with a button that has a black border with white background for the button with black text.  In this case the black border of the button fails with the dark blue page background – but that’s not really relevant because the black border passes with the white button background on the inside of the button.  Should this pass as well even though it’s dealing with the button border and the inside background of the button?

More specifically I was also asking about the state language as well not specifically about the graphic portion because the language is slightly different there.

Related to my second point on 1.4.1.  Do you have any thoughts?

Jonathan
From: Michael Gower <michael.gower@ca.ibm.com>
Sent: Tuesday, May 1, 2018 10:27 AM
To: Jonathan Avila <jon.avila@levelaccess.com>
Cc: WCAG <w3c-wai-gl@w3.org>
Subject: Re: Understanding of SC 1.4.11

Hi Jon,
I've contributed to a number of rewrites, and if you're asking questions, obviously I need another kick at the can. Note that in the latest version I gave Alastair, I'm recommending some visual examples for both boundary and 'adjacent colors' which may clarify your first paragraph questions.

> In one case we talk about the boundaries with the adjacent background and the other the adjacent background of the component.  When we measure contrast what is the contrast requirement? for both sides of the border or only for one side?  Does it matter if it’s the inside or the outside?

So the SC text talks about "visual information used to indicate...boundaries of user interface components". It also talks about "parts of graphics required to understand content". Two different things, which will both come into play in answering your question.

We only care about the contrast with the outside of any boundary of the UI component when meeting the first bullet of the SC. The issue here is that if there is a visual indication of the boundary, we want more users to be able to detect it. So if there is a visual indication, it must meet minimum contrast. Note that this doesn't require a boundary; if no one is shown the boundary of the component, then everyone is equally not shown.

For the second part of the bullet, we care about the contrast between parts of the graphic that convey meaning. In a situation where the graphic is a UI component, a few things come into play. Let's first off assume there is no visual boundary for the control. Where I have a monochromatic shape, I only care about the contrast between its edge and the adjacent background. Where I have a two-colour shape, I'll need to care about all edges of both colors, both where they meet, and where they meet the adjacent background color.
If there is a boundary, I'm going to care about its outside edge as per the first bullet of the SC. But I am also going to care about the division between the inside edge of the boundary and any internal graphic of the component IF that division contributes to the understand of the shape. In other words, is the boundary separated from the internal shape (by the background page color) or does the boundary edge meet the internal shape?


Michael Gower
IBM Accessibility
Research

1803 Douglas Street, Victoria, BC  V8T 5C3
gowerm@ca.ibm.com<mailto:gowerm@ca.ibm.com>
cellular: (250) 661-0098 *  fax: (250) 220-8034



From:        Jonathan Avila <jon.avila@levelaccess.com<mailto:jon.avila@levelaccess.com>>
To:        WCAG <w3c-wai-gl@w3.org<mailto:w3c-wai-gl@w3.org>>
Date:        2018-04-30 12:11 PM
Subject:        Understanding of SC 1.4.11
________________________________


1.       Seeking clarity on contrast of bounds/state



In reading through the understanding doc on SC 1.4.11 non-text contrast I wanted to make sure I understand the following statement regarding the contrast “visual boundaries of the component must have sufficient contrast with the adjacent background” and also regarding the state “ adjacent background of the component.”



In one case we talk about the boundaries with the adjacent background and the other the adjacent background of the component.  When we measure contrast what is the contrast requirement? for both sides of the border or only for one side?  Does it matter if it’s the inside or the outside?



2.       Seeking clarity on reference to SC 1.4.1 Use of Color in understanding 1.4.11.



I agree with what is written under the note SC 1.4.1.  But the references seem a little out of place and I think it might be worth discussing to make sure we are all on the same page.  The way I read the reference is that states used for adjacent controls such as to indicate that one toggle button is pressed and another is not cannot rely on difference lightness unless the lightness is >= 3:1.  The exception is if the state is also communicated with some other visual mechanism then the contrast between states can use any ratio of lightness.       I’ve always read 1.4.1/1.4.3 this way but wanted to understand the reference to 1.4.1 to understand were one should be flagging this issue.   Should it be flagged under 1.4.1 Color or 1.4.11 non-text contrast if no other mechanism is available other than contrast < 3:1 to show state?



Jonathan