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Re: CIE color definitions in CSS3 color module

From: Alan Gresley <alan@css-class.com>
Date: Sat, 18 Sep 2010 11:25:12 +1000
Message-ID: <4C9414F8.1000709@css-class.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: Alexis Shaw <alexis.shaw@gmail.com>, www-style@w3.org
Tab Atkins Jr. wrote:

> I would much rather wait for a hypothetical future display device to
> become real before trying to address its needs.  Engineering to meet
> predicted future needs has a generally poor track record on the web.


Agree.


>>> Note, as well, that CSS generally assumes that colors exist in the
>>> sRGB colorspace, and defines interpolation for things like transitions
>>> and gradients in terms of that space.
>>>
>>> ~TJ
>>
>> Yes, that is the challenge, it is not simple algorithms. For CIE xy
>> chromaticity space and CIE xyY color space [1] we see this.
[snip]
>> 1.
>> <http://en.wikipedia.org/wiki/CIE_1931_color_space#The_CIE_xy_chromaticity_diagram_and_the_CIE_xyY_color_space>
> 
> 
> If there's no simple algorithm to convert from CIE spaces to sRGB,
> then this is dead in the water, isn't it?


Yes, remember I didn't propose this. I protested it.


> Browsers work with colors
> in sRGB.


Correct.


> You can sometimes specify colors that officially lie outside
> the sRGB gamut, but it's clamped appropriately when actually fed to
> the device.


Really, what are they?


> If there's no good algorithm to convert from CIE colorspaces to the
> gamut used by current devices, and no actual devices that display
> colors in the CIE colorspace gamuts, then what's the use of specifying
> colors in a CIE colorspace today?
> 
> ~TJ


No use as yet for the holy grail of color spaces. This is why I 
believe Alexis or whoever should focus more on other color spaces [1] 
such as LAB [2], LUV [3], HVS and most importantly CMYK [4] which is 
used for printing.


1. <http://en.wikipedia.org/wiki/List_of_color_spaces_and_their_uses>
2. <http://en.wikipedia.org/wiki/CIELUV_color_space>
3. <http://en.wikipedia.org/wiki/Lab_color_space>
4. <http://en.wikipedia.org/wiki/CMYK_color_space>


-- 
Alan http://css-class.com/

Armies Cannot Stop An Idea Whose Time Has Come. - Victor Hugo
Received on Saturday, 18 September 2010 01:25:42 GMT

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