W3C home > Mailing lists > Public > w3c-wai-au@w3.org > October to December 1999

colors, color palettes, and textual equivalents (was re: skill level)

From: Gregory J. Rosmaita <unagi69@concentric.net>
Date: Tue, 30 Nov 1999 20:21:49 -0500
Message-Id: <4.1.19991130171113.00ae8d10@pop3.concentric.net>
Message-Id: <4.1.19991130171113.00ae8d10@pop3.concentric.net>
Message-Id: <4.1.19991130171113.00ae8d10@pop3.concentric.net>
To: Kynn Bartlett <kynn-hwg@idyllmtn.com>
Cc: Authoring Tools Guidelines List <w3c-wai-au@w3.org>
aloha, kynn!

you observed:
  If my mom wants to make a web page have a particular shade of blue
  background, she just points at that color on a color wheel and clicks --
  if she were blind, she'd have to learn RGB codes most likely.  This is
  the distinction you're making, correct?

i can't speak for charles (and, since i began composition on this, he's spoken
for himself), but my answer to your question is, yes, she would most likely
need a crib sheet that contained the RGB codes and their named equivalents --
and it would be helpful (er, beneficial) if the tool either provided one, or
pointed her to one (through a references section of the Help or Documentation)

this is a topic -- the color palette problem -- that i've addressed in
conformance evals for both AU and UA...  in my conformance evaluation of MSIE5,
NN 4.8,and Opera 3.60, performed with HAL95 back in september for the User
Agent working group, i made the following comments:

Checkpoint 1.4: Ensure that the user can configure the user agent in a device
independent manner. [Priority 1]

One of the strategies used by blind and low vision cybernauts operating in the
GUI environment is to force the user agent to ignore author-defined colors for
hyperlink text, so that it is always displayed in a consistent, uniform manner.
This includes the use of user-defined colors for visited and unvisited links,
which is not only useful for the low vision user, but also for the blind user.
Under adverse circumstances (which, for the purposes of this review includes
using HAL with Netscape), a blind user will be forced to use screen review
commands to have the font attributes for a character (or a selected/highlit
string of text) spoken, so as to ascertain whether or not the mouse-emulation
cursor is positioned on a hyperlink, and whether or not that hyperlink has been
previously selected. All three of the user agents examined in this evaluation
offer the user some level of control over the visual presentation of hyperlink
text. [NOTE: Please refer to the comments on Checkpoint 9.6 for further
discussion of this issue.] Of the three, Opera offers the greatest amount of
user configurability for hyperlink presentation -- enabling the user to
configure the browser so that, for example, unvisited links are underlined and
visited hyperlink text appears struck-through, thereby allowing the user a
supplemental means of distinguishing between visited and unvisited links. All
three user agents provide the user with the ability to define his or her own
color scheme for visited and unvisited links, along with the option to override
colors defined for a document by the document's author. All three, however,
also fail to provide alternative textual equivalents for the colors available
to the user, instead presenting the choice of colors as a palette comprised of
"swatches-in-a-box", which are completely inaccessible to the blind user
without sighted assistance. 

the reference to Checkpoint 9.6 points to the following comments:

Checkpoint 9.6 For a selected link, provide information to help the user decide
whether to follow the link. [Priority 3] 
Note. Useful information includes: whether the link has already been visited,
whether it designates an internal anchor, the type of the target resource, the
length of an audio or video clip that will be started, and the expected natural
language of target resource. 
Note. Using color as the only distinguishing factor between visited and
unvisited links does not suffice since color may not be perceivable by all
users or rendered by all devices.

REVIEWER'S GENERAL NOTE: Using HAL's "Speak background and foreground color"
and/or "Speak font attributes" key command, when the point of regard is a
hyperlink allows the user to ascertain a limited amount of information about
the currently selected link. The information that is available is as follows
(NOTE: the terminology used to enumerate information about font attributes
available to the user on demand, does not correspond to the syntax used in

"Say Font Attributes" (LeftControlKey+F) 
  1. font family (e.g. Times New Roman) 
  2. font weight (bold or normal) 
  3. font style (italic, underline, strikethrough, etc) 
  4. font size (in points) 
"Say foreground and background color" (LeftControlKey+5) 
  1. foreground color 
  2. background color 

When querying HAL as to the fore- and background colors for hyperlink text,
however, HAL was only able to report those colors defined using the hexadecimal
notation (i.e. "#RRGGBB") and not those defined using the semantic equivalents
defined for HTML4 (i.e. white, blue, red, etc.) which can be used to define
colors in CSS. Despite this, hexadecimal color values are reported by HAL in
plain English (e.g. the hexadecimal value "#00009C" is reported as "very dark
blue", while the style defined as "background-color : white;" is reported as
"background color unknown".

and, in my badly-in-need-of-an-update conformance eval of HomeSite 4.01,
located at
i made the following observations on color palettes and their usefulness:

7.2 Allow the author to change the editing view without affecting the document
markup [Priority 1] 
The editing view can be changed without affecting the document's markup. A very
nice feature of HomeSite in this regard is that, unlike most GUI applications,
the color palette is not only iconically/graphically demarcated, but is also
textually demarcated. The author can change the following screen attributes for
the editing view: 
    Font family 
    font size 
    Tab width 
    foreground color 
    background color 
In addition, the author can edit HomeSite's color coding scheme--a mechanism
which controls the display of the various components of a document as a means
of providing visual cues. The components which can be color coded include: 
    Allaire Cold Fusion Tags 
    Default Text 
    HTML Anchor Tags 
    HTML Attributes 
    HTML Image Tags 
    HTML Special Characters (character entity sets) 
    HTML Style Tags 
    HTML Table Tags 
    HTML Tags 
    JavaScript Identifiers 
    JavaScript Keywords 
    JavaScript Methods 
    JavaScript Numbers 
    JavaScript Strings 
    JavaScript Symbols 
    Microsoft ASP Tags 
    Punctuation (such as braces) 
    Script Tags 
    StyleSheet Properties 
    StyleSheet Selectors 
    StyleSheet Values 
According to the reports of sighted colleagues, when using the "Edit"
workspace, HomeSite recognizes page components and changes the color scheme
accordingly, providing a visual means of cueing the author not only to the
page's components, but quickly alerting the sighted author when he or she has
failed to correctly close containing tags, forgotten punctuation, etc. The main
failing of the color scheme feature is that the color palettes offered for
foreground and background colors do not contain textual equivalents of the
colors displayed. 

why would knowing the color values assigned to different snippets of code be of
use to a totally blind user?  

if the blind user knows what background and foreground colors have been defined
to visually symbolize different components, he or she could then set his or her
screen reader to change pitch, speed, or voice in response to color changes --
a kludge that allows for the user to obtain an aural equivalent of the color
changes, thus giving the blind user a clearer conception of the page
components, without forcing the user to review the source
character-by-character (which is what i tend to do, and which may explain my
stunted personality and complete and utter lack-of-a-real-life)

of course, the color swatches would need to be properly labeled with some sort
of understandable text -- at least the hexadecimal or RGB value, at best a
named color (when available) -- so that the label can be read or felt when the
swatch is tabbed-to, rather than merely exposed when pointed-to via a

He that lives on Hope, dies farting
     -- Benjamin Franklin, Poor Richard's Almanack, 1763
Gregory J. Rosmaita <unagi69@concentric.net>
   WebMaster and Minister of Propaganda, VICUG NYC
Received on Tuesday, 30 November 1999 20:14:46 UTC

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