I On Mixing Colors of Light

[sophiecentaur]

so that the brain doesn't have enough context

Absolutely. That's why people were happy with Technicolor at the time in a darkened cinema. Watching TV in a room with the Sun streaming in is a much more stringent requirement.

People should make a point of reading your post. Your points are well made but not everyone is aware. I have to respect the methods used to produce those original colour response curves in humans.

 

[Charles Link]

Very interesting for the previous two inputs. Most of my inputs have probably been at the 101 level, but the subject was really new to me when I wrote the OP. It was only after that, when the CIE chart was posted, that I discovered from a google that the chart has a 3rd coordinate for the blue response of $z=1-x-y$. I do think the subject of mixing colors of light and our perception, etc. is rather specialized with even the regular ones who are on Physics Forums. There might be a half dozen who know this subject at the 400+ level, and then many who might not know it even at the 101 level.

One additional comment I would like to make is that others have said I put too much emphasis on the pure spectral single wavelength types of color. The CIE chart is good IMO, but the spectral sources get what I think is somewhat underrepresented when they only get a line of zero area on the perimeter, leaving the whole chart with its tongue-shaped area to represent all the possible colors. The colors in any case are all made up of light from these pure spectral colors of individual wavelengths. Without these contributors, there wouldn't be any light.

It would be interesting if we had tunable type monochromatic LED's, so that the picture we see on a TV screen could be made from many monochromatic sources all on the perimeter of the CIE chart, rather than the broadband LED's (whose components also come from the perimeter) whose color coordinates are then a point near the perimeter, with a color picture typically being made from 3 of them=red, green, and blue.

 

[sophiecentaur]

It would be interesting if we had tunable type monochromatic LED's,

What would be the point? I already said that monochromatic sources (by definition) are very inefficient so why bother to try to develop a system with (how many??) sources? How many sources with different output spectrum would you propose? The layout of standard style display is pretty jam packed with LEDs so how would get a reliably bright picture for any wanted display colour.

whose components also come from the perimeter

Ye gods, what does that mean? The primaries are at the vertices of the triangle.
Could you estimate the sort of range a"tunable monochromatic source" would have. Could you fit enough on a high definition screen. Thing is that there is a very adequate gamut of possible display colours using wide band primaries so what would be the advantage of your proposed unobtainatrons?

 

[sophiecentaur]

many monochromatic sources all on the perimeter of the CIE chart,

Before you get carried away with spectral colour (again) then just look at the CIE colour chart below. The gamut of the usual primaries misses out nearly half of the perceivable colours. The reason for that is that all those cyans/greens/blues are not needed, i.e. not frequently seen in critical situations etc. They are more uniform than what the triangle includes and perceptual differences are low. Keeping the Primary Triangle the way it is has a noise advantage in the B and G channels because the range of signal levels only contains the more relevant xy values. Monochrome / spectral components between 480 and 540nm could be produced but the comittee decided that a well engineered system would not need them. BTW equal spaces between colour points on the chart do not represent equal perceptual differences - which is another way of saying what I mean.

 

[Charles Link]

@sophiecentaur Whether my explanations and interpretations are the best or not is subject to debate, but you did post the CIE color map a couple of times, and I did find that to be a very good thing, especially when I learned that the chart has what is a hidden coordinate, being actually a 3 dimensional map with the blue response of $z=1-x-y$. In that sense, I think the thread served it's purpose whether you would rate my posts with a $B+$ or a $C-$ or less.

 

[sophiecentaur]

@sophiecentaur Whether my explanations and interpretations are the best or not is subject to debate, but you did post the CIE color map a couple of times, and I did find that to be a very good thing, especially when I learned that the chart has what is a hidden coordinate, being actually a 3 dimensional map with the blue response of $z=1-x-y$. In that sense, I think the thread served it's purpose whether you would rate my posts with a $B+$ or a $C-$ or less.

You just introduced a fresh idea into the thread. You should be prepared to justify it and argue where you think my criticism is wrong. Your running critique of the thread is not actually appropriate.

 

[Charles Link]

You just introduced a fresh idea into the thread. You should be prepared to justify it and argue where you think my criticism is wrong. Your running critique of the thread is not actually appropriate.

If you are referring to post 202, it isn't worth getting excited about it. I'm out of new ideas at the moment, and what I presented in post 202 wasn't meant to be taken too seriously. Meanwhile it's cold here in Chicago, but at least I have a Starbucks a block away. Cheers. :)

 

[sophiecentaur]

it isn't worth getting excited about it.

It was hardly worth your posting it if you didn't want to discuss it. Non-sequiturs can damage a perfectly good thread.