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Re: yet another colour filter type thing

From: Doyle Burnett <dburnett@sesa.org>
Date: Wed, 10 Dec 2003 15:46:26 -0900
To: Wendy Chisholm <wendy@w3.org>, Tom Croucher <tcroucher@netalleynetworks.com>, W3C Web Content <w3c-wai-gl@w3.org>
Message-ID: <BBFCF052.1750%dburnett@sesa.org>

To The Group -

Wendy, thanks for sending these two links to resources related to color
deficiencies.  Given the recent "stuff" we've been working on related to
guideline 1.6 - this is likely valuable information.

I did some experimenting with both sites and found "Juicy Studio"
(http://www.juicystudio.com/services/colourcontrast.asp) to be the most
useful of the two resources.  And, if we go that route, it does give their
algorithm such that a person can evaluate their use of hexadecimal color
values related to brightness and contrast.  I did, however, find the
contrast algorithm on Juicy Studio to be a bit confusing but maybe that's
just me.  

On the other hand, the resource at - http://colorfilter.wickline.org/ did
not yield true color renditions of (at least) my own color issues.  The
site, when using the red/green color blindness link indicated that I'd see
red as green - this is just not accurate (in my case).  Please note, I say
in my case as I really do think that there are too many variables to be
certain that someone else with red/green color blindness sees what I do.
Are there others in the list with color issues that can chime in on these

Dr. Cynthia A. Brewer (Penn State) has done a lot of work related to colors
as they relate to the designing of maps.

Dr. Brewer writes - Resource at:

"Red/green color blindness is not simply a problem with confusing red and
green. It also causes problems with an unlimited pairing of colors that fall
on the confusion line. For example problems can occur distinguishing between
blue-green and pink or blue-green and purple. Color-blind individuals may
not be able to distinguish between olive-colored and rust-colored socks,
while they could distinguish between bright green and olive socks, rust and
red socks or rust and bright green socks.

One way to avoid confusion is to alter the lightness and darkness of the
colors. The color-blind person may still see the same color, but they can
tell that the areas colored with these colors are different."

"We do not know what color-blind people see," says Brewer. "Actually, we do
not know what color vision looks like to anyone but ourselves. However, if a
map has adjacent patches that someone sees as the same color, the
information stored in the map will be inaccessible."

The above paragraph really says it well - only the person with the color
deficiency really knows what's being seen.  Many sites that have written
about color issues (red/green color blindness, in particular) have
misleading information.  At least one person I know (me) can easily
distinguish the colors red and green - some popular web sites would have
their readership believing differently.  Dr. Brewer is correct, the more the
brightness between two colors differ the better for (probably) most
individuals with color deficiency challenges. Hence, the Juicy Studio
algorithm seems to work well (at least for me).  I ran many hexadecimal
color variants (background/foreground) through their (Juicy Studio) online
test and it worked well for me.

The brightness algorithm works well (my opinion - ONLY).  This whole issue
is about educating web authors but it's NOT as easy as it would seem on the
surface.  Color blind individuals are not blind to color (one exception -
achromatopsia - black and white and grey scale about one in 33,000 have this
condition) - most color blind individuals see color!

Anyway, Wendy, thanks for this info...I like the Juicy Studio information as
a very helpful resource.  I just wish there were an easy solution to this
otherwise complex issue.  I agree with Mat M. that we need to keep whatever
we come up with simple.


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

On 12/10/03 12:03 PM, "Wendy A Chisholm" <wendy@w3.org> wrote:

> Juicy Studio implemented the color contrast algorithm from AERT.
> Colour Contrast Analyser -
> http://www.juicystudio.com/services/colourcontrast.asp
> At 07:09 AM 10/11/2003, Tom Croucher wrote:
>> http://colorfilter.wickline.org/
>> This looks interesting. Try running it on one of your pages.
>> Tom
Received on Wednesday, 10 December 2003 19:45:26 UTC

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