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Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

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Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#31

Post by fc417fc802 »

RetroTechie wrote: post #25

If you're using 4 of them versus 3, wouldn't this require 1/3 more subpixels to achieve the same display resolution in pixels? Or -using same # of subpixels per cm^2- would perceived display quality be similar due to better color representation?

Yes, it would require more. No, at least assuming the pixels aren't well below the eye's spatial resolution limit then resolution will impact perceived quality much more than color accuracy. Consider what lossy image codecs like to do to chroma and why that is.

However, there are tasks that benefit from better color reproduction. There are also screens where the pixel size is well below the human discernable limit.

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#32

Post by extesy »

summa_tech wrote: post #20
layer8 wrote: post #19

Earlier quoted context omitted.

You are probably familiar with the horseshoe-shaped chromaticity diagram [0] of human-visible colors. A light source with three color primaries spans a triangle in that coordinate system. To cover the whole horseshoe, at least one of the vertices would need to be way outside the horseshoe. With four color primaries, you get a quadrilateral that makes it easier to cover a larger portion of the horseshoe. The reason th…

Excellent explanation. I'd like to add that no light source can lie outside the horseshoe of the CIE xyz diagram: pure wavelengths are points on the curved line, everything that mixes them moves towards the inside of the space. So you're stuck with triangles that fit within it.

What does it mean then for ProPhoto RGB triangle to be outside of the horseshoe on that diagram?

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#33

Post by gallerdude »

layer8 wrote: post #19
noelwelsh wrote: post #2

Can anyone explain how this works? Humans have 3 (sometimes 4) cones, so I thought that going beyond 3 primaries wouldn't increase the perceivable gamut. Update: thanks for all the great explanations!

You are probably familiar with the horseshoe-shaped chromaticity diagram [0] of human-visible colors. A light source with three color primaries spans a triangle in that coordinate system. To cover the whole horseshoe, at least one of the vertices would need to be way outside the horseshoe. With four color primaries, you get a quadrilateral that makes it easier to cover a larger portion of the horseshoe. The reason th…

This was a really fun visualization, so I vibecoded it.

https://www.jackgaller.com/colorspace

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#34

Post by loloquwowndueo »

khalic wrote: post #3

Preventing selection is quite the useless and user antagonistic pattern...

Disable JavaScript. A site abuses its privilege to execute code in your browser? Take the privilege away. Extensions like uBlock or no script can do this.

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#35

Post by AprilArcus »

extesy wrote: post #32
summa_tech wrote: post #20

Earlier quoted context omitted.

Excellent explanation. I'd like to add that no light source can lie outside the horseshoe of the CIE xyz diagram: pure wavelengths are points on the curved line, everything that mixes them moves towards the inside of the space. So you're stuck with triangles that fit within it.

What does it mean then for ProPhoto RGB triangle to be outside of the horseshoe on that diagram?

It uses nonphysical "imaginary" primaries that have meaning within the coordinate system but not within the human perceptual system.

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#36

Post by khalic »

PhunkyPhil wrote: post #30
ChrisMarshallNY wrote: post #7

Earlier quoted context omitted.

Yeah. That was crazy. I've not encountered that, before.

I knew I was a highlighter but reading that showed me how much my brain relies on spam click highlighting to keep my eyes on track. I should probably read more books.

Fascinating! I wondered why some people did that

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#37

Post by AprilArcus »

NoMoreNicksLeft wrote: post #11
Daneel_ wrote: post #5

Earlier quoted context omitted.

Cyan is severely under-represented by monitors, so the extra pixel is a dedicated cyan. It dramatically improves the ability to display blue/green colours. *edit: found the link I was after on this: https://moultano.wordpress.com/2026/06/19/where-to-find-the-...

I was under the impression that yellow was a better candidate for this. But whatever. Can hardly wait for RGBCYM televisions that will make my wallet bleed.

The chromaticity diagram is basically a straight line between 640nm (red) and 545nm (green), so anything in between (including pure yellow around 570nm) can be reproduced with a linear combination of red and green.

RGBY televisions do exist, but their goal is to boost brightness in the yellow region, not color gamut.

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#38

Post by pohl »

gallerdude wrote: post #33
layer8 wrote: post #19

Earlier quoted context omitted.

You are probably familiar with the horseshoe-shaped chromaticity diagram [0] of human-visible colors. A light source with three color primaries spans a triangle in that coordinate system. To cover the whole horseshoe, at least one of the vertices would need to be way outside the horseshoe. With four color primaries, you get a quadrilateral that makes it easier to cover a larger portion of the horseshoe. The reason th…

This was a really fun visualization, so I vibecoded it. https://www.jackgaller.com/colorspace

Nice. If I add a primary and then clicking optimize—without first moving the primary—it seem as though there are still only 3 primaries, because the new one doesn't move.

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#39

Post by SAI_Peregrinus »

khalic wrote: post #3

Preventing selection is quite the useless and user antagonistic pattern...

It's unmaintained, and off-topic for this discussion, but the Luminous JS event blocker¹ was cool because it allowed blocking specific event handlers while still allowing JS to execute.

¹https://gbaptista.github.io/luminous/doc/en-US/

Re: Multi-Primary Color Display Emerges as Next-Gen Color Reproduction Technology

#40

Post by mitthrowaway2 »

noelwelsh wrote: post #2

Can anyone explain how this works? Humans have 3 (sometimes 4) cones, so I thought that going beyond 3 primaries wouldn't increase the perceivable gamut. Update: thanks for all the great explanations!

There's a lot of great explanations here, but none that quite put it the way I'd think of it.

If we had primary color wavelengths that could stimulate each cone independently, then it would work just like you say, and we'd only need 3 of them. But because the cone spectra overlap, we don't have "orthogonal basis vectors" to work with. Our primary colors each excite a mix of cone responses.

But no problem right? As long as each primary color has a different response, we at least have linearly independent vectors, and any student of linear algebra knows you can mix those together to act as an orthogonal basis and get any desired excitation of the cones. Right?

And that would be true, except that linear algebra assumes you can freely add or subtract vector amplitudes, but with LEDs we can only generate light, we can't send a beam of "negative green". So we're constrained to the subset of colors where the basis vectors all have positive amplitudes. And that's the smaller color space that results.

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