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Re: CSS Transparent Background and 1.4.3?


From: Moore,Michael (Accessibility) (HHSC)
Date: Jan 24, 2017 10:38AM

It's like my first CS prof used to tell me. If you are not in control who is. Programming the colors eliminates surprises.

Mike Moore
EIR (Electronic Information Resources) Accessibility Coordinator
Texas Health and Human Services Commission
Civil Rights Office
(512) 438-3431 (Office)

Making electronic information and services accessible to people with disabilities is everyone's job. I am here to help.

-----Original Message-----
From: WebAIM-Forum [mailto: <EMAIL REMOVED> ] On Behalf Of Jim Homme
Sent: Tuesday, January 24, 2017 11:18 AM
To: WebAIM Discussion List < <EMAIL REMOVED> >
Subject: Re: [WebAIM] CSS Transparent Background and 1.4.3?

From the below, I'm translating that the test is inclusive, and that to ensure a valid test, we should advise the developer to code an explicit background color. Is that accurate?



=========Jim Homme,
Team Lead and Accessibility Consultant,
Bender HighTest Accessibility Team
Bender Consulting Services, Inc.,

-----Original Message-----
From: WebAIM-Forum [mailto: <EMAIL REMOVED> ] On Behalf Of Patrick H. Lauke
Sent: Monday, January 23, 2017 7:19 PM
Subject: Re: [WebAIM] CSS Transparent Background and 1.4.3?

On 23/01/2017 18:28, Jim Homme wrote:
> Hi, According to what I just read, transparent is the default if a CSS
> background color isn't coded by the developer. Since I'm totally
> blind,, how does that affect testing for 1.4.3, contrast? For
> instance, are the results different for black text on a white
> background, specifically coded, than they are if the developer just
> specifies black text and allows the default to take over?

Assuming you mean a developer doesn't set explicit background color anywhere, including the body/html elements:

- browsers used to default to a medium/light grey colour as the default; however, most (all?) browsers these days default to a white default for the body/html

- users *may* have specified that their browser should use specific custom default colours. For this reason, not specifying at least an explicit colour for the body/html elements in addition to a foreground colour would lead to the explicitly defined foreground colour being displayed over any kind of colour - making this impossible to test for conclusively since it will depend on the user's settings (unless your evaluation explicitly mentions that the result is only valid for default browser values).

Patrick H. Lauke

www.splintered.co.uk | https://github.com/patrickhlauke http://flickr.com/photos/redux/ | http://redux.deviantart.com
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