Talk:rg chromaticity

Question

Who knows the questions?

Why usually to use the rg chromaticity,why not to use rb or gb chromaticity.

Thanks！ —The preceding unsigned comment was added by Jackie5168 (talk • contribs) .

Rg chromacity of black.

When R+G+B is 0, should (r,g) be (0,0) or (1,1)? --24.131.215.166 (talk) 03:26, 13 October 2008 (UTC)

Undefined, obviously, since the divisor is zero. Black does not have a chromaticity, in general (undefined x,y,z coordinates). Dicklyon (talk) 03:29, 13 October 2008 (UTC)

(1,1) would not be ok because r+g+b=1 and thus would give b=-1. (0,0) on the other hand would give b=1 which would correspond to blue. But incorporating that black should not have a chromaticity which is given by r=g=b another solution would be (1/3,1/3) MasterLee (talk) 15:44, 29 January 2024 (UTC)

Linearity and Gamma

The article should mention whether the sum R + G + B is done with linear or nonlinear RGB values. The article mentions 8-bit RGB values (0 .. 255), which traditionally have a gamma value implied; in the case of gamma 2.2 an RGB value of 128 would indicate a 22% light intensity (one half to the power of 2.2). On the other hand, normalized RGB values are usually taken to be linear, so a value of 0.5 indicates 50% light intensity. The article should be clear about which is which. See the article about standard RGB for details. 80.171.110.26 (talk) 05:35, 13 December 2013 (UTC)

Given how much of an ad hoc hack this is, I'd say it's done on sRGB. Or whatever non-linear RGB you happen to have. It's computer vision, not quite an exact science -- they sometimes use HSL (also defined over "whatever RGB available") and say it works well too. --Artoria2e5 🌉 18:48, 8 July 2021 (UTC)

Conversion to RGB

If G = 0, the conversions back to R and B won't work.

Slapdash5 (talk) 04:42, 8 February 2019 (UTC)

True, if you mean from r,g,G space, then G=0 leaves the conversion completely ambiguous. That's not a fault of the equations. Dicklyon (talk) 05:47, 8 February 2019 (UTC)

Confusion with CIE

The entire section with the RGB color-matching functions confuses the computer "RGB" with the CIE 1931 RGB. These two systems have nothing to do with each other; in particular, you are never going to build a light with negative energy emission at a certain wavelength. I propose removing this part completely -- in fact, I will remove it if I check back a month later and see no objection. --Artoria2e5 🌉 18:51, 8 July 2021 (UTC)

Njm7203, I am extremely sorry for being harsh AF, but... I am planning to revert your work and I think you should be notified. --Artoria2e5 🌉 18:56, 8 July 2021 (UTC)

Do you plan on following this up? Curran919 (talk) 20:26, 10 November 2022 (UTC)