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RE: Color contrast principle

From: Jonathan Avila <jon.avila@levelaccess.com>
Date: Wed, 16 Jan 2019 17:09:46 +0000
To: Detlev Fischer <detlev.fischer@testkreis.de>
CC: Alastair Campbell <acampbell@nomensa.com>, "WCAG list (w3c-wai-gl@w3.org)" <w3c-wai-gl@w3.org>
Message-ID: <DM6PR03MB42810389DDD1AF5ECF967CFAF1820@DM6PR03MB4281.namprd03.prod.outlook.com>
Hi Detlev, I would be ok with something like outline as long as it provided flexibility for situations such as situations where the outline didn’t cover the entire element or where the outline varied such as with drop shadows, etc. or non-uniform edges.

Jon

From: Detlev Fischer [mailto:detlev.fischer@testkreis.de]
Sent: Wednesday, January 16, 2019 3:43 AM
To: Jonathan Avila
Cc: Alastair Campbell; WCAG list (w3c-wai-gl@w3.org)
Subject: Re: Color contrast principle

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Hi Jon,
I think we are roughly on to the same thing but I find the talk about points quite hard to understand (aren‘t we dealing with surfaces and (out)lines, mostly?
Sent from phone

Am 16.01.2019 um 01:24 schrieb Jonathan Avila <jon.avila@levelaccess.com<mailto:jon.avila@levelaccess.com>>:
I’d say something like – when determining adjacent colors to points – an adjacent point that is not immediately touching the initial point can be used for the comparison when the sum of corresponding points communicates the same information needed to identify parts of the control or graphic and its states.   That is the sum of adjacent but not touching points produces the same information necessary to identify the object.

Jonathan

From: Alastair Campbell <acampbell@nomensa.com<mailto:acampbell@nomensa.com>>
Sent: Tuesday, January 15, 2019 7:05 PM
To: WCAG list (w3c-wai-gl@w3.org<mailto:w3c-wai-gl@w3.org>) <w3c-wai-gl@w3.org<mailto:w3c-wai-gl@w3.org>>
Subject: Color contrast principle

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Hi everyone,

There was some confusion on the call about the second example under the “Adjacent colors” heading here:
https://cdn.staticaly.com/gh/w3c/wcag/non-text-contrast-updates/understanding/21/non-text-contrast.html?x=5

<image002.jpg>

The aim was to show a general principle of measuring adjacent colours, perhaps it needs some adjustment?

The principle is that: If there is a non-contrasting colour between two contrasting ones, assume that it merges with the non-contrasting colour, then does it pass?

In that case, assume the silver border merges into the blue background, so it is essentially white vs dark blue.

This is important because it meets the user-need and allows for many more design possibilities. (Designs that would fail the SC without causing an impact on people.)

Without that, it would essentially mean two-colour only controls.

There is a similar principle going on for the radio-button example (selected / not-selected) further down.
<image004.jpg>

All of those pass, but the middle two demonstrate the principle that if the middle contrasts with the outside, we can ignore the outer circle of the radio – it is a change of shape.

If anyone can think of a better explanation for the understanding doc… I’m all ears!

Kind regards,

-Alastair

--

www.nomensa.com<http://www.nomensa.com/> / @alastc

Received on Wednesday, 16 January 2019 17:10:12 UTC

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