On 15 Jul 2003 19:18:38 -0700, (optidud) wrote:

When viewing thru a flourite such as the FS-102 which
corrects for the color Green, Blue and Red, how come
the Violet blur can't be seen as if invisible? Only triplets
such as the AP, TMB, etc. corrects for Violet too but
not in the FS-102 or FC series yet the Violet fringe
that is supposed to be there can't be seen. However,
when we look at a person with a violet shirt, we can
see it, so what's the difference in the uncorrected
violet blur color of the doublets and the shirt. Both
should register violet. Even after consulting many sites
on vision and color. The explanation still eludes me.

-snip-

the anwser is how we see colour, not optical theroy.

You see (poun intended), nto all peopel with so called
"normal" colour see colour the same. Teh textbook answer is people
with "normal " colour vbision see from 400nm (violet) to 700nm (deep
red). But evidence has shown some peopel see well into the near
ultra-violet. I think the US military is atually conducting tests to
see just how far, but published reports in trade journals suggest on
some individuals human sigt can go as deep or far as 320 nm into the
near ultra-violet.,

The other problem si when you are looking at a shirt, you may
or may not be seeing all that violet light. Some peopel cna also see
into the near IR according to some theories, so if the person is
wearing a cotton shirt - cotton reflects IR light - as iopposed to say
apolyester shirt - polyester passes IR light - the coloru cast of the
shirt may differ, even if the same dye is used on both fabrics.

I coudl go on and on, but yes, you are correct, most web site,
IMO, suck big tiem when ti comes to anexplaination fo human colour
vision. Even medical sites. They just simply don't get it.
joe



http://www.oneilphoto.on.ca