Fw: PC warning signs

["Megan E. McMacken" <megan -dot- mcmacken -at- FANUCROBOTICS -dot- COM>]

Posted for Geoff Hart...


Greets!

Hope this provides some useful information. Please forward it to
techwr-l so others can correct me or elaborate. (I can't post
directly.) Thanks!

--Geoff
********

Megan McMacken wondered about color and other cues to use for
onscreen warnings and cautions. A few thoughts:

I've got very serious reservations about using colors to denote
degrees of warning because enough of the population has
some form of colorblindness (men are particularly often affected,
and particularly for red/green distinctions) that relying on color
can defeat the purpose of the warnings. The rule of thumb for using
color cues is to ensure that there is at least one other visual cue
that differentiates between two otherwise similar symbols. When
you're working solely with color, one thing that greatly helps is
to choose colors that have strongly different values (degrees of
blackness underlying the color), so even colorblind viewers can see
that the symbols are different. (You can confirm whether your color
choices work simply by photocopying the two colors on a black and
white copier: if they're still distinct, you've made a good color
choice.) Worse yet, your manager is dead wrong in claiming that color
transcends national/cultural backgrounds... William Horton, among
many others, have convincingly proven that colors vary enormously in
their associations. That's not to say that people can't learn how
you're using color... they can. But if your audience is culturally
diverse, you can't rely on them to automatically understand the
meanings of your colors; you'll have to train them first.

But I doubt that such subtle differences in color will be effective
if that's all you're using to catch and hold the viewer's attention,
and if there are lots of notes (which viewers start to ignore after a
while) and only a few warnings (which they should _never_ ignore),
the warnings won't stand out enough to be noticed... they'll blend in
with all the other triangles. You can solve the problem by using two
simple, universally (well... almost) understood shapes: the triangle
used for "yield" road signs (i.e., proceed carefully, and pay
attention) and "stop" signs (i.e., don't proceed under any
circumstances; stop and look and think it through). Use the yellow
and red colors too, by all means, because these do help... but don't
rely solely on the color.
--Geoff Hart @8^{)}
geoff-h -at- mtl -dot- feric -dot- ca

Hart's corollary to Murphy's law: "Occasionally, things really do work
right."