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Re: Graphics contrast - critical principle

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Tue, 6 Dec 2016 14:08:17 -0600
Message-ID: <CAOavpvegKSZJjSQkswiNWC8BmvONmFhb=MZcs7P1A=-QeHEqVA@mail.gmail.com>
To: Alastair Campbell <acampbell@nomensa.com>
Cc: James Nurthen <james.nurthen@oracle.com>, WCAG <w3c-wai-gl@w3.org>, Glenda Sims <glenda.sims@deque.com>, public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org>
Hi Alastair and all,

I agree, Alastair, the heart of the Informational Graphic Contrast
Issue [1] is that the test should be: For each element of a graphic
required for understanding, it is discernible.

Does anyone not agree with that?

However, as James and Glenda pointed here on the list, examples that
involve text should be covered with 1.4.3. In addition we should
probably change the image in issue 9 [1] showing the 24px (large) text
to an image that doesn't use text. Josh pointed out in the survey [2]
that can be confusing too.

Kindest Regards,
Laura

[1] https://github.com/w3c/wcag21/issues/9
[2] https://www.w3.org/2002/09/wbs/35422/NewSC_20161122/results#xq2


On 12/6/16, Glenda Sims <glenda.sims@deque.com> wrote:
> Alastair, c: James et al
>
> I love this!  But James has a good point, I think example 2 needs to focus
> on the color contrast between meaning non-text items.
>
> So...you can make reference to the grey text on the different colors (but
> say that is out of scope for this SC...because it is covered by 1.4.3 ).
>
> Then...in Example two..compare the color contrast for:
>
>    1. 46% ORANGE pie slice against PURPLE pie slice
>    2. 24% PURPLE pie slice against RED pie slice
>    3. 20.4% RED pie slice against GREEN pie slice
>    4. 5.1% GREEN pie slice against ORANGE pie slice
>    5. 1.3% PURPLE pie slice against ORANGE pie slice
>
> I see you've got interesting things going on with borders on the pie slices
> (I bet to help with color contrast).  I didn't list all the combinations
> that are really being tested for each pie slice...because there is
> "overlap"...but for clarity it might be worth listing every one.
>
> What do you think?
> G
>
> glenda sims    |   team a11y lead   |    deque.com    |    512.963.3773
>
>
> *web for everyone. web on everything.* -  w3 goals
>
> On Tue, Dec 6, 2016 at 11:39 AM, James Nurthen <james.nurthen@oracle.com>
> wrote:
>
>> Alistair,
>>
>> Example 2 in here is really confusing me.  Can you explain how this
>> differs from 1.4.3 as I believe the text in this image is already covered
>> by WCAG.
>>
>> Regards,
>>
>> James
>>
>> On 12/5/2016 6:58 AM, Alastair Campbell wrote:
>>
>> Hi everyone,
>>
>>
>>
>> Thanks for all the feedback on Information graphics contrast [1, 2].
>> There
>> is one principle involved, which if agreed, means we can refine the
>> wording
>> and continue.
>>
>>
>>
>> Several people noted the difficulty with testing contrast on complex
>> graphics which have multiple colours, which is true on the face of it.
>>
>>
>>
>> I think there is a reasonable way to approach this, which I tested by
>> presenting it to 8 people in our design team. They didn’t go pale or get
>> angry, and after a couple of examples it seemed quite reasonable.
>>
>>
>>
>> We obviously haven’t conveyed it in the SC text well enough yet, but if a
>> few of the respondents could read this and think through the objections,
>> I
>> think we can clear that stumbling block:
>>
>> https://alastairc.ac/tests/graphics-contrast-explanation.html
>>
>>
>>
>> The nub of it is that the test should be: *For each element of a graphic
>> required for understanding, it is discernible.*
>>
>> That is very different from contrast-testing every combination of
>> elements, and IMHO much more feasible.
>>
>>
>>
>> In that page I work through a couple of the examples to show what’s
>> needed. It is also worth noting that the current “1.4.1 Use of Color“
>> catches most current “difficult” examples, the contrast aspect would help
>> catch the remaining ones.
>>
>>
>>
>> I’ve worked through a dozen examples [3], I’m happy to tackle more so
>> long
>> as they pass the color-alone SC and are different from ones I’ve already
>> done.
>>
>>
>>
>> Kind regards,
>>
>>
>>
>> -Alastair
>>
>>
>>
>> 1] https://github.com/w3c/wcag21/issues/9
>>
>> 2] https://www.w3.org/2002/09/wbs/35422/NewSC_20161122/results#xq2
>>
>> 3] https://alastairc.ac/tests/graphic-contrast-test.html
>>
>>
>> --
>> Regards, James
>>
>> [image: Oracle] <http://www.oracle.com>
>> James Nurthen | Principal Engineer, Accessibility
>> Phone: +1 650 506 6781 <+1%20650%20506%206781> | Mobile: +1 415 987 1918
>> <+1%20415%20987%201918> | Video: james.nurthen@oracle.com
>> Oracle Corporate Architecture
>> 500 Oracle Parkway | Redwood Cty, CA 94065
>> [image: Green Oracle] <http://www.oracle.com/commitment> Oracle is
>> committed to developing practices and products that help protect the
>> environment
>>
>


-- 
Laura L. Carlson
Received on Tuesday, 6 December 2016 20:08:53 UTC

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