[whatwg] Colour correction (was: Canvas ImageData comments)

Darin Adler darin at apple.com
Sun Jan 20 09:58:36 PST 2008

On Jan 20, 2008, at 9:10 AM, Henri Sivonen wrote:

> Most of the time, the solutions to the color space problem are worse  
> that the problem itself. The easiest fix for this whole mess would  
> be making Mac OS X default to 2.2 gamma (i.e. be compatible with the  
> overall legacy instead of the Mac legacy) and then continue to treat  
> Web color values as being in the system color space.
> At least in order to avoid Breaking the Web, browsers need to treat  
> all untagged colors in a mutually consistent way within a browser  
> window regardless of the source of the color: image files, CSS,  
> plugins, video, legacy HTML attributes, etc. The usual way to do  
> this is to treat all untagged color values as being in the system  
> color space.

Good explanation.

The proposal from color experts here at Apple is to interpret untagged  
colors in the sRGB color space. This is what's done with most other  
untagged color in Mac OS X.

But this rule not yet implemented in WebKit. Instead, when displaying  
on screen, today's WebKit treats untagged color as if it was in the  
system's primary display device's color space. This means that no  
color correction is applied to such colors.

I'm not certain exactly what the "system" color space is or whether  
the Mac OS X gamma difference from Windows is important when designing  
this. I think the sRGB design is a good one. When displaying color on  
devices with unusual color characteristics, it doesn't make sense to  
display color with no correction at all.

     -- Darin

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