John Woelflein wrote:
> The different
> colors help the general population (except those who are color blind)
> to discern the different notes.
Only about one person in 25 000 is truly color blind (gray vision).
I think about one man in 10 is red/green deficient (i.e., somewhat skewed in
favor of blue, typically to a small extent). Some men are red blind or green
blind (I forget the proportion). Blindness to red AND green (blue-gray
vision) is quite rare.
I have a red-green deficiency, sufficient to fail an Ishihara test. However,
it gives me trouble only in identifying colors (or perceiving differences)
where red or green content is very low. Bank notes, of course, tend to use
quite distinctive colors (sufficiently distinct that I've never had a
problem with them).
Not relevant to the main topic, of course. (Hence my caveat in the subject
line.)
Bill Potts, CMS
Roseville, CA
http://metric1.org [SI Navigator]
