Talk:rg chromaticity

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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 (talkcontribs) .

Rg chromacity of black.[edit]

When R+G+B is 0, should (r,g) be (0,0) or (1,1)? -- (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)

Linearity and Gamma[edit]

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. (talk) 05:35, 13 December 2013 (UTC)