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Old 22nd November 2018, 12:54   #1  |  Link
mzso
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How many colors do we need to completely cover human vision?

Hello!

I'm curious about this.
The familiar CIE "horseshoe" diagram implies to me that it can be done. Though I have no idea what the x/y axis represent I assume they can't go to negative, or zero.
Color systems clearly can go past the the edge of the "horseshoe" curve. As shown on the image for ProPhoto RGB.
By the looks of it the curve could be contained with a 4-5 corner (color) polygon.
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Old 22nd November 2018, 13:55   #2  |  Link
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Most humans can discern about 10 millions colors, although there are supposed to be a few that can see in the region of 100 million.

Color vision table, The table about 2/3 the way down the page.
https://en.wikipedia.org/wiki/Color_vision

Insects eg some bees and birds, eg humming birds can see in the region of 10 billion colors (some humming birds and bees can see in the Ultra Violet, and eg Rattle Snakes can see in the Infra Red [although not with their eyes, special pits approx where nostrils would be]).
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Old 22nd November 2018, 19:13   #3  |  Link
mzso
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Originally Posted by StainlessS View Post
Most humans can discern about 10 millions colors, although there are supposed to be a few that can see in the region of 100 million.

Color vision table, The table about 2/3 the way down the page.
https://en.wikipedia.org/wiki/Color_vision

Insects eg some bees and birds, eg humming birds can see in the region of 10 billion colors (some humming birds and bees can see in the Ultra Violet, and eg Rattle Snakes can see in the Infra Red [although not with their eyes, special pits approx where nostrils would be]).
Perhaps. But it's not really relevant. By mixing three colors we can cover the majority of human perception, as shown by the triangles on the picture.
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Old 22nd November 2018, 22:33   #4  |  Link
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the number of colors is irrelevant it's more about the max wavelengths.the answer to the number of colors would be 3 because the x/y can be negative check out XYZ.
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Old 22nd November 2018, 23:07   #5  |  Link
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Quote:
Originally Posted by mzso View Post
Perhaps. But it's not really relevant. By mixing three colors we can cover the majority of human perception, as shown by the triangles on the picture.
I think you're going to have to be a lot more rigorous about this question if you want a meaningful answer. Rigorously define what you mean by color and coverage, just for starters.
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Old 22nd November 2018, 23:50   #6  |  Link
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Quote:
Originally Posted by mzso View Post

I'm curious about this.
The familiar CIE "horseshoe" diagram implies to me that it can be done. Though I have no idea what the x/y axis represent I assume they can't go to negative, or zero.
Color systems clearly can go past the the edge of the "horseshoe" curve. As shown on the image for ProPhoto RGB.
By the looks of it the curve could be contained with a 4-5 corner (color) polygon.
If you're referring to the CIE chromacity diagram, ProPhoto does not have complete coverage

But yes , it can be completely covered and exceeded, by ACES for example . It has been used in actual production workflows for a few years now .

https://commons.wikimedia.org/wiki/F...olorspaces.svg

Open Source tools like Natron can handle ACES with opencolorIO, and blender has limited support too
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Old 23rd November 2018, 01:38   #7  |  Link
mzso
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I think you're going to have to be a lot more rigorous about this question if you want a meaningful answer. Rigorously define what you mean by color and coverage, just for starters.
Well, I thought I did that particularly with the picture, where triangles are drawn for different colorspace that don't completely cover the area that represents human vision.

Anyway. What I meant was how many wavelengths/frequencies of colors (instead of RGB) to be mixed. (in a pixel for example)
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Old 23rd November 2018, 01:40   #8  |  Link
mzso
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the number of colors is irrelevant it's more about the max wavelengths.the answer to the number of colors would be 3 because the x/y can be negative check out XYZ.
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Originally Posted by poisondeathray View Post
If you're referring to the CIE chromacity diagram, ProPhoto does not have complete coverage

But yes , it can be completely covered and exceeded, by ACES for example . It has been used in actual production workflows for a few years now .

https://commons.wikimedia.org/wiki/F...olorspaces.svg

Open Source tools like Natron can handle ACES with opencolorIO, and blender has limited support too
Ah, cool. Good to know.
What wavelength colors does it use? Is it still RGB? (And only more bits are required)

(Hopefully someone will update the more used image file I got from wikipedia with this colorspace)

Last edited by mzso; 23rd November 2018 at 01:51.
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Old 23rd November 2018, 02:34   #9  |  Link
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there is again no answer to the bit deep question.
even 1 bit is enough if the resolution(of cause the get totally out of hands with 1 bit but not with 6 bit) is high enough and brightness has an effect on the needed bit deep too and here starts the next question what is the "maximum brightness".

XYZ is not RGB based as far as i know; https://en.wikipedia.org/wiki/CIE_19...E1931_rgxy.png
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Old 23rd November 2018, 03:10   #10  |  Link
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Originally Posted by mzso View Post
Ah, cool. Good to know.
What wavelength colors does it use? Is it still RGB? (And only more bits are required)

(Hopefully someone will update the more used image file I got from wikipedia with this colorspace)
ACES is RGB based.

Typically 16bit half float , or 32bit full float are used . I don't know if there is a "minimum" value, but I've never seen anything ACES related below 16bit half float.

Even though the values are represented by ACES , no current display will show all of them (ie. no current display has full ACES coverage) . So right now it's just used in acquisition and post production workflows, not for end delivery

https://en.wikipedia.org/wiki/Academ...ncoding_System
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Old 23rd November 2018, 13:16   #11  |  Link
mzso
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there is again no answer to the bit deep question.
even 1 bit is enough if the resolution(of cause the get totally out of hands with 1 bit but not with 6 bit) is high enough and brightness has an effect on the needed bit deep too and here starts the next question what is the "maximum brightness".

XYZ is not RGB based as far as i know; https://en.wikipedia.org/wiki/CIE_19...E1931_rgxy.png
I don't think dithering to simulate brightness levels is strictly relevant to this though.
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Old 23rd November 2018, 13:31   #12  |  Link
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I think when asking how many bits are required, it is safe to assume that low resolution is implied (e.g. just two big pixels next to each other).
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Old 23rd November 2018, 18:49   #13  |  Link
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and again no answer to that how is the light distributed gamma, PQ, linear or some new form, how is it powered does it need processing before.
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Old 25th November 2018, 04:12   #14  |  Link
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The deeper you try to understand how human vision works, especially color vision, the more "it depends" comes up. :/

The Royal Institution, The Physics and Psychology of Colour - with Andrew Hanson
https://www.youtube.com/watch?v=af78RPi6ayE
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Old 25th November 2018, 08:36   #15  |  Link
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Quote:
Originally Posted by mzso View Post
What I meant was how many wavelengths/frequencies of colors (instead of RGB) to be mixed. (in a pixel for example)
JFYI, The electro magnetic spectrum is a continuum.

Continuum
Noun: continuum (continua, continuums)
A continuous nonspatial whole or extent or succession in which no part or portion is distinct or distinguishable from adjacent parts.
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Old 25th November 2018, 23:16   #16  |  Link
mzso
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JFYI, The electro magnetic spectrum is a continuum.

Continuum
Noun: continuum (continua, continuums)
A continuous nonspatial whole or extent or succession in which no part or portion is distinct or distinguishable from adjacent parts.
True. But human vision is not equipped to discern arbitrary frequencies. It can be (apparently completely) fooled by three colors of a particular frequency.
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Old 26th November 2018, 03:33   #17  |  Link
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the AVG human as 3 cones and the brain and some cells uses a lot of math to do the "rest".
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Old 26th November 2018, 18:59   #18  |  Link
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True. But human vision is not equipped to discern arbitrary frequencies. It can be (apparently completely) fooled by three colors of a particular frequency.
Not completely, and certainly not by using the peak cone response frequencies. And practicalities mean that the typical colours used in displays are a compromise. You can't replicate the deep violets you see in a sunset on a typical RGB display, for example.
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Old 26th November 2018, 20:39   #19  |  Link
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Not completely, .
Well, that's not what the triangle for the ACES colorspace suggests. (Image linked above)

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And practicalities mean that the typical colours used in displays are a compromise. You can't replicate the deep violets you see in a sunset on a typical RGB display, for example.
This is of course true, for the time being.
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Old 27th November 2018, 00:19   #20  |  Link
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Lasers are great for exploring the limits of color vision, you can get a lot of pure colors that you cannot represent with any normal display (or normal objects). You don't usually see yellows or blues that color. A 473 nm laser is a cyan that is way outside what a normal display can do. It looks weird.
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