Sorry, there was a missing character in the final link. Here is the correct link. _Goethe’s Theory of Colors from the Perspective of Modern Physics_ https://www.physikdidaktik.uni-wuppertal.de/fileadmin/physik/didaktik/Forschung/Publikationen/Grebe-Ellis/Mack_und_Goethe_Seite_124-137_freigegeben-low.pdf
Harry On Thu, Aug 31, 2023 at 4:05 PM H L V <hveeder...@gmail.com> wrote: > What is yellow? by PehrSall > https://www.youtube.com/watch?v=X_1WiWGndZw > > PehrSall is a physicist who is interested in the history and science of > color theory. He has many video's in which he investigates Newton's and > Geothe's color theories experimentally. > > He also has a video on Land's two color investigations. > https://www.youtube.com/watch?v=YG4bzGNc1E0 > > In this beautiful investigation > _Goethe's Purple Ray - alias Monochromatic Rays of Shadow, the > Rehabilitation of Darkness_ > https://www.youtube.com/watch?v=vu_7uG6KlsU > he argues that Newton did not demonstrate that white light consists of > variously coloured lights any more than he was able to demonstrate the > 'absurd' thesis that darkness consists of variously coloured shadows. > (Personally I am not sure that the absurdity of one thesis should be > regarded as proof that both theses are unjustified. I am inclined to ask > what if the absurd thesis were true?) > > > This paper supports my opinion that there is still much to learn about the > nature of radiation. > > Power Area Density in Inverse Spectra > https://arxiv.org/ftp/arxiv/papers/1706/1706.09063.pdf > > An informal discussion of the results of the same paper in german and > english with more pictures: > > https://www.physikdidaktik.uni-wuppertal.de/fileadmin/physik/didaktik/Forschung/Publikationen/Grebe-Ellis/Mack_und_Goethe_Seite_124-137_freigegeben-low.pd > > > Harry > > > On Sun, Aug 27, 2023 at 2:59 AM MSF <foster...@protonmail.com> wrote: > >> The delay? I don't think we're in a hurry. And clearly no one else on the >> list has an interest in our discussion. >> >> Spectral colors and their perception are my business. I've made literally >> billions of square meters of diffraction gratings, mostly decorative >> patterns. Yellow and magenta have been particularly interesting to me for a >> few reasons. I am of the controversial opinion that yellow doesn't exist >> except in human perception. >> >> Years ago, before lasers became unbelievably inexpensive, I was >> interested in creating a light source to view transmission holograms >> without a laser or filtered mercury arc. I had a lot of slide projectors >> left over from my "psychedelic light show" so I thought I could use one to >> make such a light source. I put a slit into the projector where the slide >> would normally go and a high efficiency Bragg diffraction grating in front >> of it. This projected a nice broad spectrum. I then used another slit to >> isolate whatever color I wanted and a cylinder lens to spread it out. This >> worked quite well, but not very bright. I settled on what would normally be >> called the yellow part of the spectrum. >> >> But people viewing the holograms this way would say that the color was >> white, or perhaps gray. I thought the same thing. You have to see this to >> appreciate it. So maybe Roy G Biv should change his name. Another example >> of the phenomenon is a pressure tuned krypton laser. At just the right gas >> pressure it makes four more or less equally spaced colors if sent through a >> prism: red, yellow, green, and two tightly spaced blues. The yellow looks >> yellow when the other colors are present, but by itself it appears to be >> colorless. A lot of people smarter than I have argued about these things >> for a very long time. >> >> If you really want to see some strangeness as regards color perception, >> look up Land color theory. I played around with this when I was a child, >> and my family thought I was nuts. >> >> I just think it's a gift to us that we can perceive color the way we do. >> >> ------- Original Message ------- >> On Thursday, August 24th, 2023 at 9:10 AM, H L V <hveeder...@gmail.com> >> wrote: >> >> Sorry about the delay. >> >> I am not sure. If you think about it, overlapping colours don't go along >> with the topology of stress lines. >> However, cellophane tape is a different situation. It could be that the >> perception of the colour magenta is situational like >> the perception of yellow. >> >> >> Did you know that a third class of mammalian photoreceptors was >> discovered in the 1990's? >> Intrinsically photosensitive retinal ganglion cell were only shown to be >> definitively present in humans in 2007 in people who were born without rods >> and cones. >> >> From wikipedia " ipRGCs were only definitively detected in humans during >> landmark experiments in 2007 on rodless, coneless humans.[15] >> <https://en.wikipedia.org/wiki/Photoreceptor_cell#cite_note-ns1-15>[16] >> <https://en.wikipedia.org/wiki/Photoreceptor_cell#cite_note-mnt-16> As >> had been found in other mammals, the identity of the non-rod non-cone >> photoreceptor in humans was found to be a ganglion cell in the inner >> retina. The researchers had tracked down patients with rare diseases wiping >> out classic rod and cone photoreceptor function but preserving ganglion >> cell function.[15] >> <https://en.wikipedia.org/wiki/Photoreceptor_cell#cite_note-ns1-15>[16] >> <https://en.wikipedia.org/wiki/Photoreceptor_cell#cite_note-mnt-16> >> Despite having no rods or cones the patients continued to exhibit circadian >> photoentrainment, circadian behavioural patterns, melanopsin suppression, >> and pupil reactions, with peak spectral sensitivities to environmental and >> experimental light matching that for the melanopsin photopigment. Their >> brains could also associate vision with light of this frequency." >> >> Harry >> >> >>
