WebAIM - Web Accessibility In Mind

E-mail List Archives

Re: Color Contrast - where to measure?

for

From: Brian Ward
Date: Aug 14, 2023 5:01PM

Schalk,

That documentation definitely helps. It does seem to give priority to the
colors placed in the code over how the anti-aliasing creates a new color on
the user's screen. I would have hoped the priority would be the other way
around. I have a case where the color contrast between foreground and
background is at 5.5 according to the code, but in actuality, its about 2.5
as measured by the eyedropper in WCAG Color Contrast tool. That's due to
the very thin lines and anti-aliasing. The software vender says they are in
compliance. I was hoping to force to the issue and say no they are not, but
according to this documentation, they meet the letter of the law, but not
the spirit.

Brian

*Brian Ward*
Instructional Technologist
Instructional Design and Technology
208-467-8359
Book a Meeting With Me <https://calendar.app.google/ecJNrPLxvaKMBjMY7>

*IDT Resources*

NNU Teaching Toolkit <https://nnu.instructure.com/courses/29924>

Canvas Guides <https://community.canvaslms.com/t5/Guides/ct-p/guides>

TA Request Form: Course Help
<https://docs.google.com/forms/d/e/1FAIpQLSfl5LRsJiVFpeTDZW2pihnUXMLO7WKMec-Mwj3noOz723b6Kg/viewform?usp=sf_link>

TA Request Form: Test Building
<https://docs.google.com/forms/d/e/1FAIpQLScAw_pB0UGP55Kw_0g1CajYktfVCTlirN1JC7mER8wauE0zTQ/viewform?usp=sf_link>


<https://www.nnu.edu?utm_source=signature&utm_medium=email&utm_campaign=nnu>


On Mon, Aug 14, 2023 at 4:40 PM Schalk Neethling < <EMAIL REMOVED> >
wrote:

> Hey Brian,
>
> The following note from the web content accessibility guidelines page on
> color contrast for text makes for some interesting reading.
>
> "Because authors do not have control over user settings for font
> smoothing/anti-aliasing, when evaluating this Success Criterion, refer to
> the foreground and background colors obtained from the user agent, or the
> underlying markup and stylesheets, rather than the text as presented on
> screen."
>
> https://www.w3.org/WAI/WCAG21/Understanding/contrast-minimum.html
>
> > refer to the foreground and background colors obtained from the user
> agent
>
> I assume this means getting the color values using the browser's developer
> tools, but perhaps picking the colors using a color picker from the page as
> displayed in the user agent also counts. I would be curious to know what
> others think.
>
> The above then also only covers text contrast, but there are also images
> of text and non-text contrast that are detailed separately.
>
> --Schalk Neethling
> Founder, Teacher, Frontend Engineer
> Mechanical Ink
> https://mechanical.ink
>
> ---
>
> Mechanical Ink Studio Podcasts
>
> The Mechanical Ink podcast
> https://pod.link/1657505237
>
>
> Join me in taking actionable steps to help the climate:
> http://bit.ly/3uDVT1c
>
> Sent with Proton Mail secure email.
>
> ------- Original Message -------
> On Tuesday, August 15th, 2023 at 00:12, Brian Ward via WebAIM-Forum <
> <EMAIL REMOVED> > wrote:
>
>
> > I am in discussions with Canvas LMS accessibility group about color
> > contrast of many of their button/icons. When I check them with Color
> > Contrast tools (via eyedropper) some of them fail contrast standards.
> When
> > I pointed this out to Canvas, their reply was to show me the coding for
> the
> > color of the text or icon (foreground) and background and that there is
> > enough contrast.
> >
> > So my question is where is the standard applied? On the end user side via
> > what their screen perceives, or in the underlying code? Is it what the
> > eyedropper pulls up for color or what the programmer entered?
> >
> > The end user side is affected by font choice, line thickness, aliasing,
> > etc., screen resolution, screen zoom settings, etc. I get that, but the
> > eyedropper tool seems the best way to objectively pick up on what the
> > perception is.
> >
> > Can anybody provide any documentation on this?
> >
> > Thanks,
> >
> > Brian
> >
> > Brian Ward
> > Instructional Technologist
> > Instructional Design and Technology
> > 208-467-8359
> > Book a Meeting With Me https://calendar.app.google/ecJNrPLxvaKMBjMY7
> >
> >
> > IDT Resources
> >
> > NNU Teaching Toolkit https://nnu.instructure.com/courses/29924
> >
> >
> > Canvas Guides https://community.canvaslms.com/t5/Guides/ct-p/guides
> >
> >
> > TA Request Form: Course Help
> >
> https://docs.google.com/forms/d/e/1FAIpQLSfl5LRsJiVFpeTDZW2pihnUXMLO7WKMec-Mwj3noOz723b6Kg/viewform?usp=sf_link
> >
> >
> > TA Request Form: Test Building
> >
> https://docs.google.com/forms/d/e/1FAIpQLScAw_pB0UGP55Kw_0g1CajYktfVCTlirN1JC7mER8wauE0zTQ/viewform?usp=sf_link
> >
> >
> >
> >
> https://www.nnu.edu?utm_source=signature&utm_medium=email&utm_campaign=nnu
> >
> >
> > --
> > This e-mail message (including any attachments) is for the sole use of
> the
> > intended recipient(s) and may contain confidential, privileged, and/or
> > proprietary information. If the reader of this message is not the
> intended
> > recipient, you are hereby notified that any dissemination, distribution
> or
> > copying of this message (including any attachments) is strictly
> prohibited.
> >
> > If you have received this message in error, please contact the sender by
> > reply e-mail message and destroy all copies of the original message
> > (including attachments).
> > > > > > > > >

--
This e-mail message (including any attachments) is for the sole use of the
intended recipient(s) and may contain confidential, privileged, and/or
proprietary information. If the reader of this message is not the intended
recipient, you are hereby notified that any dissemination, distribution or
copying of this message (including any attachments) is strictly prohibited.

If you have received this message in error, please contact the sender by
reply e-mail message and destroy all copies of the original message
(including attachments).