Would it change your mind if you saw the real thing instead of a digital representation? All of color photography, both on film and now with digital cameras and LCD or OLED screens depend upon acceptable approximations of the real colors. This varies among different cultures.
And now, I delve once more into my misty past. In the late 60s I made a meager living doing what was then called a "psychedelic light show" with rock bands. One of the effects I used was a rotating polarizer combined with various crystals and injection molded styrene. I used to search grocery and hardware stores for suitable pieces. I would then use them as is or further stress them by heating and stretching. You can definitely see edges of red and blue around the magenta. Something even more definitive could be seen when making patterns from the original Scotch cellophane tape. After they switched to polypropylene, much to my disappointment at the time, the effect was no longer possible. As you rotate the polarizer slowly you could see a washed out red, fading into magenta and then blue. Again, probably more than you wanted to know. ------- Original Message ------- On Wednesday, August 16th, 2023 at 2:16 AM, H L V <hveeder...@gmail.com> 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. > https://www.youtube.com/watch?v=-6U4uembaNQ > > 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 <foster...@protonmail.com> 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 >> >>>>>
