RE: Colour blindness and accessibility

I'm colour blind and it has all sorts of effects on life. That said, you
also develop coping mechanisms and some of them I think are almost
subconcious. For example, general light clutter can be a problem when
driving, especially at night (green traffic lights are almost white, so
indistinguishable from motorbike headlights; the red / amber phases are
similar to sodium street lights at night). But there are secondary clues to
help: phase / sequence of lights, white borders round traffic lights etc.

The biggest single work, non-web, problem I have springs from a lack of
knowledge from potentially anyone who ever sends me a document or email, not
just developers: people using red text (within a generally black-on-white
document) to flag up important information, changes etc. Everyone just
assumes that red is prominent. In practice I can't see it, at least without
a major effort of concentration. If I had to choose a colour that really
leapt out at me against a white background, it would be bright blue (hex
code #0000ff - go too much darker or lighter and it starts to lose its
contrast). Incidentally, I think contrast is important, but it is often
discussed in terms of foreground contrast against the page background. In
practice, contrast against other foreground objects is as, if not more,
important. A highlighted red word amongst black text on a white background
is bad not because it can't be read against the white background - it can,
it's easy - but because it cannot be distinguished from the surrounding
black text. So the "information content" that is lost is the emphasis, not
the content.

I work in an office, so I am sure that the problems of someone who operated
e.g. machinery would be very different (for example, green "go" / red "stop"
switches). However, at least in that type of situation, if the designer /
developer / whatever is aware of the issues, they can design and test the
interface properly. Whereas within an office environment, effectively anyone
in any organisation who ever sends you anything to look at becomes an
"interface designer" for that document. With the best will in the world, I
don't suppose everyone is going to become sensitive to the problems of us
colourblind people, let alone every other accessibility issue, so I guess
there will always be problems to be faced.


-----Original Message-----
From: Lois Wakeman []
Sent: 29 April 2003 11:17
Subject: Colour blindness and accessibility

Someone contacted me via my web site and asked if I could give any examples
of how colour blindness affects people in their work - not just web sites,
but office and industrial equipment etc. Is there anyone here who can
provide her with some practical examples?
If so, please contact Ingeborg Marie Dehs Thomas at

See below for the original email.

Lois Wakeman

I am a graduate in product design and am presently doing a project for the
Ministry of Social Affairs and Employment in Holland. The aim of the project
is to create awareness and enthusiasm around their policy to enhance the
work environment for all. (For more information, please go to )
I have chosen colourblind as my main target group. I have searched the web
about colourblindness, which is how I have found your contact details. While
I do feel a little wiser about colourbindness on a general level, I am still
very keen on understanding how the everyday life at work is for someone who
is colourblind.
I am wondering if you can help me to find information about the little
annoying things of a colourblind person's everyday life. Things that
designers just never thought about during the design process (while dyslexia
is very common in art schools, I doubt that colourblindness is).
I am unaware as whether colourblindness is even considered a disability, but
I hope to be able to improve a product or situation that may have been
overlooked by others, and that still may be annoying for colourblind.

I  look forward to hearing from you.

Yours sincerely,
Ingeborg Marie (Emily) Dehs Thomas

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Received on Tuesday, 29 April 2003 08:15:30 UTC