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Re: Notes from Matt McMahon presentation on color blindness at UW

From: Doyle Burnett <dburnett@sesa.org>
Date: Wed, 14 Jan 2004 11:20:05 -0900
To: Joe Clark <joeclark@joeclark.org>, W3C Web Content <w3c-wai-gl@w3.org>
Message-ID: <BC2AD665.1BA1%dburnett@sesa.org>

Joe and The List -

Joe, I am in total agreement with what you said in this recent post and what
your chapter on color deficiency had to say, generally speaking.

If one looks at the information from [1] below and checks the colors from
figure 16, the RGB values DO NOT match what the author had claimed the
values to be. I used a tool much like the one that can be used as a part of
Photoshop and a few other software programs that allows me to obtain RGB and
other color related values. In the case of looking at the ColorBrewer
generated color values - they ALL matched with regard to RGB values.  This
made me believe that the tool I was using to ascertain RGB values must be
pretty accurate as the values I derived were ECXACT based upon what values
were given in the ColorBrewer chart.

Although not a perfect solution and possibly not what was intended (although
Ms Brewer has stated publically in a presentation that her work can be used
for the web) - the ColorBrewer scheme "could" work to benefit web developers
with regard to selecting appropriate color combinations.

Joe, you are being listened to and your chapter on color deficiency is on
the mark, in my opinion.  As a person with significant color deficiency
issues plus a host of other vision challenges, I can appreciate the complex
nature of this subject.  Deriving a specific formula/algorithm for making
color choice determinations is no easy task because literally, nobody can
walk in the color deficiency shoes of another.  Personally, I appreciate the
calm approach that you took in your most recent response to the list as it
was more or less affirmation that maybe we are moving in the correct
direction.  Thanks for you input.

[1] http://jfly.iam.u-tokyo.ac.jp/html/color_blind/#pallet

Sincerely -

Doyle Burnett

Doyle Burnett
Education and Training Specialist
Multiple Disabilities Program
Special Education Service Agency

On 1/14/04 10:42 AM, "Joe Clark" <joeclark@joeclark.org> wrote:

>> I am using a Macintosh G3 desktop computer and realize that colors across
>> browsers, operating systems and monitors "may" vary with regard to perceived
>> colors.  But, RGB values, if used correctly, should render the same value,
>> regardless of a users perceived notion of color.
> This seems contradictory. The RGB value (if you're using that colourspace)
> is a fixed thing, but it is indeed the manifestation and perception that
> count. And those two things will vary, especially for older people with
> acquired colour deficiency, as through yellowing of the iris.
>> In relationship to checkpoint 1.6, we really are not concerned about a users
>> ability to see and identify color - we are concerned about their ability to
>> see text that is presented over background colors.  The Brewer Palette and
>> her use of color spaces may be a valuable resource.
> Well, I coined the term "Brewer Palette," I documented her work for a lay
> Web-design audience, and the ColorBrewer tool is not really useful for Web
> design per se.
> <http://joeclark.org/book/sashay/serialization/Chapter09.html#p-1725>
> (Hi, Chris!)
> In the usual course of events, it doesn't matter how a colour is perceived
> by the Web visitor. The goal is to avoid confusion or illegibility. It is
> quite possible to use confusable colours (as red and green or blue and
> green and the analogous hues along those colour lines) in unconfusing
> ways. It's up to the designer to make reasonable choices, and, if there is
> a likelihood of difficulty in reading, to provide stylesheet-switchers or
> a similar mechanism. Failing that, it's up to the reader to take matters
> into his or her hands and employ, for example, a user stylesheet.
> An author who didn't want to go to all that trouble, but who still wanted
> to use a variety of colours, could simply use the Brewer Palette, which
> contains hues that even colour-deficient people (at least with congenital
> colour deficiencies-- it hasn't been tested with acquired deficiencies to
> my knowledge) can tell apart and whose names everyone agrees on.
> I think this is now my second year of telling the Working Groups the same
> things over and over and over again, including at the Toronto f2f, and
> simply having it all ignored. When *are* you going to cut that out?
> --
> Joe Clark  |  joeclark@joeclark.org
> Author, _Building Accessible Websites_
> <http://joeclark.org/access/> | <http://joeclark.org/book/>
Received on Wednesday, 14 January 2004 15:19:08 UTC

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