Jim Green asked for more comments about whether people "see" colors
differently. I think one problem with this question is the muddling of the
words "see" and "perceive" and "describe."
Assuming the eyes' sensors are basically working properly (i.e. we have two
people with "normal" vision), they might indeed use different words to
describe what they see. But that does not necessarily mean they actually
sensed different things... they might just describe it differently.
I have an ongoing argument with my wife about the color blue. She wants to
call cyan blue. The color I call blue she wants to call violet. I can take
a cyan filter, run the light through a diffraction grating, and show her
beyond doubt that there is just as much green in the light as there is blue.
She agrees. When we look at the projection screen she sees the band of
color start the same place I do and end the same place I do. See agrees the
green part looks the same brightness or even a bit brighter than the "blue"
part. I show her another filter (I call blue) and run it through the
diffraction grating and she admits it looks the same as the cyan filter with
the green removed. Have I made my point? No, she still says the cyan is
what she calls blue and my "blue" is what she calls violet.
I am totally convinced we see the same thing. We just describe it
differently.
Related topic. John Denker is certainly correct that brightness is
important. That is why so many astronomy students are disappointed when
they look through the telescope and see Orion's Nebula in black-and-white
when they were expecting to see it in color. All the pictures they've seen
of neat astronomical objects are in color. Why doesn't it really look that
way? Too dim for the eye to perceive the color... that's why.
Also when I have talked about star colors with students, and have examined
stars both with naked eyes and with telescopes, they often disagree on
whether it is red or orange or yellow. I assume this is partly a brightness
issue, but also partly the "descriptive issue" I've described above. I
personally don't describe Betelgeuse as a red star, I think it is more
orange than red. Some students don't even think it is orange, and they call
it yellow. I have indeed observed some carbon stars with the telescope that
I would definitely describe as red. Some of my students don't even see
these at all. For the real faint stuff they don't have the patience and
they also have a hard time trying to look at things through the telescope
with peripheral vision rather than direct view. Peripheral vision is often
better at picking out faint stuff. That's another reason people might
disagree about what they see. When I am looking in an eyepiece of a
telescope I try to use both direct and peripheral vision (back and forth) to
see everything I can see. It took me a while to train myself to do that.
Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817