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Re: Color contrast (Minimum)

From: Olaf Drümmer <olaflist@callassoftware.com>
Date: Tue, 16 Aug 2016 22:00:43 +0200
Cc: Olaf Drümmer <olaflist@callassoftware.com>, Wayne Dick <waynedick@knowbility.org>, Elizabeth Pyatt <ejp10@psu.edu>, "Ta, Duc" <duc.ta.740@my.csun.edu>
Message-Id: <FC3CBD5F-8F8B-4983-A126-28AF7EA2470A@callassoftware.com>
To: w3c WAI List <w3c-wai-ig@w3.org>
Using Color Contrast Analyzer, I get this:

> Foreground: #CA0814 - Background: #000000
> 
> The contrast ratio is: 3.6:1
> 
> Text failed at level AA
> Text failed at level AAA
> Large text passed at level AA
> Large text failed at level AAA
> 
> 1.4.3 Contrast (Minimum):  Text (and images of text) have a contrast ratio of at least 4.5:1, except if the text is pure decoration.  Larger scale text (at least 18 point or 14 point bold) or images of text can have a contrast ratio of 3:1. (Level AA)
> 
> 1.4.6 Contrast (Enhanced): Text (and images of text) have a contrast ratio of at least 7:1, except if the text is pure decoration.  Larger scale text (at least 18 point or 14 point bold) or images of text can have a contrast ratio of 4.5:1. (Level AAA)
> 
> Note: Fonts that are extraordinarily thin or decorative are harder to read at lower contrast levels.

Unfortunately, while passing AA for large text, even the black on red is difficult to see for a person like me (without noteworthy vision problems).

That much said: the conversion to grayscale (using Adobe Photoshop) gives me:



which by far does not look as bad as what has been shared initially (for me it’s actually kind of OK to read).

If I use “use grayscale” in Mac accessibility settings, I get a slightly less rich in contrast version. If I activate “increase contrast” on top, I get almost the same as the original example (but still not as dark).

Important: Exercises like this are not really ‘exact science’, as there are too many uncontrolled variables.

All in all I think it is fair to say “your mileage may vary”, and as Andrew pointed out: per the contrast formula used by WCAG 2, the contrast is just fine for large text (for  AA).



Olaf



> On 16.08.2016, at 21:42, Wayne Dick <waynedick@knowbility.org> wrote:
> 
> Whether this is an image or not it's 1.41:1. Fail it.
> 
> On Tue, Aug 16, 2016 at 12:20 PM, Elizabeth Pyatt <ejp10@psu.edu <mailto:ejp10@psu.edu>> wrote:
> So what were the original color values for the reds?
> 
> I’m trying to understand how the contrast algorithm is effected when the example becomes black and white.
> If it’s a luminosity scale (i.e. values only are measured), then theoretically shifting or removing the hue should not matter. If it does, there is an issue that needs to be investigated.
> 
> Hope this makes sense.
> 
> Best
> Elizabeth
> 
> 
> > On Aug 16, 2016, at 3:06 PM, Andrew Kirkpatrick <akirkpat@adobe.com <mailto:akirkpat@adobe.com>> wrote:
> >
> > From: "Ta, Duc" <duc.ta.740@my.csun.edu <mailto:duc.ta.740@my.csun.edu>>
> > Date: Tuesday, August 16, 2016 at 13:53
> > To: Andrew Kirkpatrick <akirkpat@adobe.com <mailto:akirkpat@adobe.com>>
> > Cc: WAI-IG <w3c-wai-ig@w3.org <mailto:w3c-wai-ig@w3.org>>
> > Subject: Re: Color contrast (Minimum)
> >
> > The actual color is dark red background and the text is red. However, when I check black and white mode, it turns out to be that so i am not sure whether I should consider it as a failure or I will say it is decent and move on.
> >
> >
> > Best,
> > Duc Ta
> 
> =-=-=-=-=-=-=-=-=-=-=-=-=
> Elizabeth J. Pyatt, Ph.D.
> Instructional Designer
> Teaching and Learning with Technology
> Penn State University
> ejp10@psu.edu <mailto:ejp10@psu.edu>, (814) 865-0805 <tel:%28814%29%20865-0805> or (814) 865-2030 <tel:%28814%29%20865-2030> (Main Office)
> 
> 3A Shields Building
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> http://www.personal.psu.edu/ejp10/psu <http://www.personal.psu.edu/ejp10/psu>
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> 
> 
> 
Received on Tuesday, 16 August 2016 20:01:15 UTC

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