Which I found fascinating as you can't "fake" not being color blind.

There was one chart that I simply couldn't see the line to trace on
the chart.  I passed all other charts with flying colors (pun
intended).  I asked about this to the AME and he said if you were
color blind you would see different numbers or trace a different line
then a person not color blind on the very same chart.

Of course don't get me on the binocular test as I fail that miserably
(no stereoscopic vision)

In article
<b9a6d9ca-9114-4ed5-ae0a-6c23c79c8935@k4g2000yqb.googlegroups.com>,

In this quote note that "color balance" is not defined.

"Treatment" is not the right word to use."Modified" or "compensated"
might be a better word to use. As treatment, the method is equivalent to
treating myopia with glasses. Yjr best you can say is that myopia is
compensated. It certainly not cured.

Aside from my self education my best knowledge of color vision arises
from being lucky enough to hear several lectures by Richard Feynman. At
one public lecture with demonstrations, he went into Maxwell's three
color theory. Based on that, color blindness, Land's retinex theory,
colored lights casting shadows with colors not present, and two-strip
Cinecolor or Technicolor are readily explained.

One demonstration showed how what seemed to be projected brown light was
really just yellow light with a different relative illumination compared
to the background. The brain reinterprets color! There is no brown light.

For these and other reasons, Feynman considered COLOR MATCHING to be the
key way to quantify color vision of "normal" and other people. Different
normals tend to be be fairly consistent matching colors while calling
them with different names.

I do not make all my assertions on color on authority alone. On occasion
I have worked on colorimetry (for detectors) and densitometry. All those
fancy formulas in the books I used seem to be self-consistent.

Getting back to the topic at hand, a filter upsets color matching. If
you like that upset, use one or more different filters. In the end, I
cannot understand how any filters can end up changing the color
experience substantially.

Bill

OK, I am not *completely* color-blind to red - as I mentioned before,
I do see red, just not very well. If the ambient light is brighter, I
see red better, but if the ambient light is dim, red doesn't show up,
so I am left with the impression that the color is black (no color).
"Brighter" reds - more saturation - are easier for me to see than reds
that are darker, muddier, browner, etc. I believe that's why the
filtering out of non-red colors has an effect - less muddying of the
mix makes the red more obvious. So perhaps I have all three pigments,
but the response of the red-sensing one is attenuated for whatever
reason. So when wearing the clip-ons, the other (shorter) wavelengths
are reduced, leaving the red present in proportionally greater
amounts, and producing a more red-emphasized response to my brain.
That's my conception of the solution, anyway. (The clip-ons would be a
good solution, except they are too dark for indoor use - being
sunglasses - and they are cheap Chinese knock-offs, so the lens
material introduces some distortion as well.)

Traffic lights can be a problem. If the sky is very bright, I have a
lot of trouble seeing the red; it just isn't there, so the light
appears to be off (usually the sky isn't so bright as to cause
problems for me, but on a really sunny day...). If I don't see a green
or a yellow light, the logical conclusion is that the light is red.
There is an intersection in an adjacent town that has a light that
only operates when trains come through; if I happen by on a sunny day,
I assume the light is red, and have to take my cues from the general
traffic flow (they oughta just leave it blinking yellow). LED traffic
lights are a little easier for me to see when red.

People like to ask me what color does red look like - well, basically
it looks red, unless conditions aren't favorable for me, then it
doesn't "look" at all - usually it appears black, but with muted
shades of red, the color appears sort of brown. Also, some shades of
purple seem primarily blue.

As an aside, a while back I put a prism in a window, blocked out the
rest of the light and viewed the spectrum. I placed a mark where the
red disappeared, and my wife did the same; her mark was a good
distance from mine - into the "non-color" area. I used the tuning
capability of a spectrophotometer at work to see where my cut-off is.
Of course, it's more of a rapid fall-off, but I could see nothing past
680nm, IIRC.

This post started out as nothing more than a question about the
availability of "selective color-heightening" glasses. I still don't
know if they are available. The added discussion, as usual, has been a
nice side benefit. Is Feynman's color lecture available in print? I
know that Dover has published a lot of his lectures recently. My main
resource has been Nassau's "The Physics And Chemistry Of Color". I
guess I need to get it out and brush up.

I want to thank you and Mike for your input, and if there is more
forthcoming, I will read it (and comment where appropriate) as well.

Joe