Talk:International Commission on Illumination

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Information given on page basically is correct but not precise.

From my understanding it focuses just on one specific item CIE is famous for and does not reflect main goal of CIE. Probably selfdescription of CIE is more helpful in describing maintask of CIE (See copy below).

Existing page therefore I would like to suggest to be renamed to "CIE 1931 Color matching function". CIE 1931 is so called 2degree observer. Further investigations in human response to visible light ended in conclusion human eye responds also in range of 10degree to color. This obersvation has been standardized by CIE in 1964 in so called CIE 1964.

Be careful what you rename it! CIE standards maybe[edit]

Yes CIE should describe the international body and what their purpose is. But "CIE 1931 Color matching function". is not the proper name for the existing page, and his page should be always assesable if you click on this new CIE page. People need to refer to what standards were adopted by the CIE. Color Matching functions does not cover it all. Find a better name. [[User:Dkroll2|Dkroll2]] 13:55, Dec 14, 2004 (UTC)

Self description of CIE from their homepage:


As its name implies, the International Commission on Illumination - abbreviated as CIE from its French title Commission Internationale de l'Eclairage - is an organization devoted to international cooperation and exchange of information among its member countries on all matters relating to the science and art of lighting.

The CIE is a technical, scientific and cultural, non-profit autonomous organization. It has grown out of the interests of individuals working in illumination.

Since its inception 90 years ago, the CIE has become a professional organization and has been accepted as representing the best authority on the subject and as such is recognized by ISO as an international standardization body.

ColorRendering --[[User:Dkroll2|Dkroll2]] 15:23, Dec 14, 2004 (UTC)[edit]

Anybody watching here? Can you please have a look at ColorRendering? The article isn't perfectly clear to me and the only thing I clearly understand is the connection to CIE. -- Pjacobi 09:20, 11 Aug 2004 (UTC)

This could be one of the new designations for lighting: Color Rendering capacity?

or maybe just the plainf old useless CRI Color Rendering Index Color temperature (color) --[[User:Dkroll2|Dkroll2]] 15:23, Dec 14, 2004 (UTC)

IR limit[edit]

The 810nm limit mentioned for human eye sensivity in the red is a frequency commonly used for infrared diodes and high power infrared lasers, witch, as far as I know, are complely invisible. You can't see them even at intensities that would completly ofuscate if emitted at a more commonly accepted limit of around 750nm. -- Rnbc 1 Dec 2004

I can see the light from a Ti:sapphire laser tuned to 840 nm. The bandwidth is a couple of nm, so what I'm seeing is more likely 830 nm. Still, a beam of 600 mW on white paper appears as a feeble visible red spot, only discernible if you switch off the lights. Han-Kwang (talk) 10:16, 1 Dec 2004 (UTC)

You are perhaps seeing secondary radiation emitted from the paper, or resulting from impurities in the laser (witch also emmits at other bands, probably), or something else. 600mW is a lot of light... If I stare directly, at close range, into an 810nm diode in the dark (appears quite bright for my camera) I see nothing. I've asked a few other persons, they also see nothing... In fact 810 and 835nm are common bands for invisible lasers used for aiming rifles used when you don't want your enemy to spot you. -- Rnbc 3 Dec 2004


Can you add a sentance referring to "chromaticity Coordinates"?

You have everyting else except a senttance to that.,?

please >HR>

--[[User:Dkroll2|Dkroll2]] 15:15, Dec 14, 2004 (UTC)


Can you add a sentance referring to "chromaticity coordinates" On the CIE pages?

You have everyting else except a senttance to that.,?

please >HR>

--[[User:Dkroll2|Dkroll2]] 15:15, Dec 14, 2004 (UTC)

x and y[edit]

  1. i find the CIE horseshoe pretty confusing: why isn't it a true triangle, but rather of weird shape? A triangle would have the colors R, G and B in its corners.
  2. when there is the purple line (blue to red), why isn't here a blue-to-green line and a green-to-red-line?
  3. how do you "calculate" the CIE horseshoe? there must be some mathematical background for this figure.
  4. How do you get RGB values, given x and y? What about LMS values? thanks so much for your help, --Abdull 18:28, 19 Mar 2005 (UTC)
  5. I partially agree. Could somebody quickly explain me here what the x and y axis stand for? It's not wavelenght, it's not intensity - what is it? Maybe this info would be interesting to the article itself. Peter S. 00:28, 31 May 2005 (UTC)
  6. The end of the current article explains that the x and y axes are the two chromacity dimensions; but would someone like to make this clearer on the graph itself? jgh 2005-06-30

Hello - Please take a look at the CIE XYZ color space article, there is a more complete discussion there. It still may be too technical - if it is, could you leave comments on that talk page and I will try to address them. As for the above questions -

  1. You could distort the chromaticity diagram into a triangle, but then it would cause difficulty when doing calculations. The designers of the XYZ color space and the xy chromaticity diagram wanted it so that if you pick any two colors, any mixture of those two colors would lie on the line connecting them. You can't have that if you distort it into a triangle.
  2. The purple line (blue to red) is special. Blue, magenta, green, yellow, red, these are all monochromatic colors, you can have a single wavelength to represent them rather well. Also, you can mix blue and green to get magenta, etc. Purple (or cyan) is special. Its a mixture of blue and red, and there is no monochromatic light that is purple. The outer curved part of the chromaticity diagram holds all the monochromatic colors. If you pick any two colors on the chromaticity diagram, then the eye will be able to see all the colors on the line between the two. Any two colors. So it follows that the boundary of the bottom part of the horseshoe is the line connecting the reddest red with the bluest blue - and that is the purple line.
  3. See the CIE XYZ color space article. If you know I(λ) the spectral power distribution of the light, then you multiply it by the X, Y, and Z color matching functions and integrate. That gives you X, Y, and Z. Then you get x and y by x=X/(X+Y+Z) and y=Y/(X+Y+Z).
  4. RGB is a generic term, there's lots of RGB spaces. I think what you are referring to is the sRGB space which was designed for computer monitors, and is what Adobe Photoshop uses as RGB. Check out the sRGB color space article. About LMS, I am not sure.
  5. The x and y are qualitatively the chromaticity of the color. Two colors with different x and y are different colors. Two colors with the same x and y are the same color, although they may have different brightness. The CIE XYZ color space article describes technically what they mean.
  6. I will do that.

PAR 30 June 2005 06:46 (UTC)

Overlap with CIE 1931 color space[edit]

The title of this article suggests that it is about the organization, and the first two paragraphs fit that topic. The rest of the article, however, is about the color space developed by this organization, a topic which surely deserves its own article, and, indeed, already has its own article (CIE 1931 color space). I propose that all the description of the color space in this article be replaced by one sentence pointing to that other article, say, something like this: In 1931, the commission developed the CIE 1931 color space, which is still used as a standard reference for defining colours, and as a reference for other colour spaces. Any objections? Stebulus 18:36, 20 July 2006 (UTC)

No objections, I guess. I'll proceed as described, then. Stebulus 18:42, 27 July 2006 (UTC)