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Re: Re: CIE color definitions in CSS3 color module

From: <alexis.shaw@gmail.com>
Date: Sat, 18 Sep 2010 02:00:21 +0000
Message-ID: <00163645840eaf467004907f0a92@google.com>
To: Alan Gresley <alan@css-class.com>, Alexis Shaw <alexis.shaw@gmail.com>
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, www-style@w3.org
My main focus was on Lab and Luv.....
I do not know how this got to be a fight about XYZ, how about we put that  
issue away
and focus on Lab and Luv, with a white point of D65. oh and by the way it  
is a simple calculation
it is a 3x3 matrix multiplied by a 3 vector plus a clamp. as are all color  
conversions.

On Sep 18, 2010 11:25am, Alan Gresley <alan@css-class.com> wrote:
> 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 02:00:54 GMT

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