The demonstrations given by this lecturer are more refined so it is easier
to observe how magenta arises in proximity to other colours.

The idea that real or objective colour is reducible to a single parameter
known as wavelength seems to me simplistic and wrong. Even with the domain
of the hard sciences, colour should be treated as
a multidimensional phenomena.


On Tue, Aug 15, 2023 at 10:16 PM H L V <> wrote:

> Cool. Your story got me to watch videos of stress visualization in plastic
> using polarized light.
> Noticing how readily the  colour magenta (a.k.a. pink ) is produced in
> this video as the plastic is rotated.
> Watching how the magenta patches come and go as the viewing angle changes
> got me thinking about the common teaching that since magenta
> does not appear in Newton's spectrum it is made up by the brain whenever
> red and blue light overlap. (By contrast magenta does appear in Goethe's
> spectrum a.k.a the dark spectrum).
> Although it is certainly possible to trick the brain into seeing colours
> which aren't there such as when red and green light overlap to create the
> illusion of yellow light, this is not proof that magenta is just made up by
> the brain. On the contrary if magenta were just made up by the brain then
> _every_ instance of magenta in the above video should show signs of red and
> blue around its perimeter which is not the case.
> Harry
> On Mon, Aug 14, 2023 at 5:16 PM MSF <> wrote:
>> More polarized fun...
>> A much more easily viewed demonstration of the effect we are discussing
>> here is looking at clear glass table tops outside. If you happen to have
>> some lawn furniture that includes a clear tempered glass table top, all you
>> have to do is stand to the east or west of of the glass and look down at it
>> at an angle of approximately 56 degrees and you will see beautiful pools of
>> color. The colors outline the birefringence caused by the strains in the
>> tempered glass.
>> Once in a while a random observation at my back yard of the phenomenon by
>> a friend or family member will be alarmed at "something wrong with the
>> glass".  And of course, their eyes glaze over when I try to explain it.
>> You might wonder why I immediately recognized Harry's noticing of
>> mysterious color effects during his walk. It's simple. When I was very
>> young, I used to see these colors in the pavement all the time, directly
>> on, not peripherily. The reason is my brother and I were blessed, or
>> cursed, with vision that was so sharp and light sensitive that we were
>> accused all the time of "seeing things". We tested out at 20-05 on the eye
>> charts. Our retinas must have been so stuffed withe rods and cones, I'm
>> surprised they didn't explode. I could see close to 7th magnitude stars.
>> That's all gone now that I'm old. Down to 20-20 with lens implants.
>> Please pardon my self-indulgent nostalgia.
>> MSF

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