Wikipedia talk:WikiProject Color/Normalized Color Coordinates
Unqualified and inappropriate use of color coordinates
As any formally trained color scientist would confirm, it is inappropriate to use unqualified color coordinates to specify a color appearance. In the color item articles, as I would guess all the other color-related articles, there is a box on the upper-right of the page that pretends to state the color coordinates of the color in RGB, CMYK, HSV and Hex values. This is wholly incorrect. RGB values in themselves cannot depict color appearance. In order to do so, the RGB triplet has to be connected to physical reality through, at the minimum, the definition of the RGB color space used, the white point of the illuminant, and in certain cases, the gamma function. The ICC specifications can help one understand what these requirements are. If Prussian Blue has such and such color coordinates, they have to be qualified as, for example, in AdobeRGB color space. Better still, linear XYZ color coordinates should be used. Furthermore the conversion of RGB to CMYK is wholly dependent on the particular transfer functions used for a specific set of inks and paper combination - the idea of posting the CMYK color coordinates for a physical color appearance is naïve at best and mostly preposterous.
As such the article runs contrary to the most basic precepts of color science, and is wholly misleading to uninformed readers. Trying to digitally reproduce the appearance of Prussian Blue using the information contained herein will not work at all.
Use of sRGB as a connection space neutral ground for RGB triplets is laughable. When specifying colors that relate to the physical world, there are radiometric and photometric values one can use, that have been designed specifically for that. Photometric values such as those standardized by the CIE standards body are the ones that should be used. They won't be bound to the specific gamut of display color spaces such as sRGB. Many natural pigments fall completely outside the gamut of sRGB, and henceforth, your entire SRGB-normalized reference system collapses like a deck of cards. Being aware of the CIECAM02 model of color appearance would help convert the CIE coordinates into practical RGB values for users who wish to simulate naturally-occuring colors under specific constraints of illumination, and avoid some surprises with metameric behavior.
As it currently is, the system used in Wikipedia is completely inadequate.
There is plenty of reference available on the subject, from books by Billmeyer & Salzman for the less technically enclined, to more recent works. An authoritative source on the topic is definitely Prof. Mark Fairchild of the Munsell Color Science Laboratory in Rochester, NY. — Preceding unsigned comment added by Ppanzini (talk • contribs)
I've clicked on the color infobox's 
a few times to end up here, and I'm not sure that this page is entirely appropriate as a link from mainspace articles - the presentation is geared very much towards colour value syntax conversion and says little about the infobox or values contained therein. Would anyone agree that we need a colour analogue of Wikipedia:How to read a taxobox ? Nihiltres(t.c.s) 16:27, 8 May 2007 (UTC)
- I've started a draft of a page at Wikipedia:How to read a color infobox, though it needs major work. I hope you don't mind that I used the American spelling, but figured it should match the spelling used by the infobox. 03:54, 9 May 2007 (UTC)
Value and saturation
In the section on HSV coordinates it states that a fully saturated color should be at 50% value as in the Munsell system, but the example box shows a fully saturated orange with a value at 100%. Which is the preferred method for Wikipedia? Justin Foote (talk) 00:38, 28 September 2008 (UTC)