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Re: [CSS21] Test Suite

From: Chris Lilley <chris@w3.org>
Date: Fri, 23 Jul 2004 23:47:54 +0200
Message-ID: <1789136985.20040723234754@w3.org>
To: Henri Sivonen <hsivonen@iki.fi>
Cc: www-style@w3.org

On Friday, July 23, 2004, 11:30:44 PM, Henri wrote:

HS> On Jul 24, 2004, at 00:23, Chris Lilley wrote:

>> On Friday, July 23, 2004, 11:03:31 PM, Henri wrote:
>> HS> Being able to contain color space info is no good when the 
>> HS> software has no idea about the color space of the display device.
>> Although you are no worse off in that situation either.

My comment assumed that the implementation would do no correction if it
had no idea what to correct *to*.

HS> Actually, you are. See http://iki.fi/hsivonen/png-gamma.html

I agree with your two concluding sentences:

>> I’d like to ask implementors of applications that deal with PNGs to
>> pay attention to consistent color handling and not to do arbitrary
>> gamma changes when the gamma properties of the output device are just
>> guesses. Also, please treat the colors of PNGs with no color space
>> information the same way you would treat the colors any other image
>> file that doesn’t carry color space information.

The sentence before that is arguable, it depends on the intent:

>> ’m sure many designers would agree that color consistency within a
>> page is more important than color sameness across different computers
>> or operating systems.

One statement is false that I can see:

>> However, the implementors weren’t sufficiently warned about the
>> effects of gamma “correction” in situations where the image is not in
>> isolation, so instead of fixing the original problem PNG gamma
>> “correction” created a new, even worse problem: inconsistent color
>> within a Web page.

Yes, they were sufficiently warned and at the same time that PNG was
going through standardization at W3C, so was the concept of identical
color handling in CSS colors.

That the implementors failed to do what the spec said (they had agreed
the spec should say) cannot be blamed on not being informed about it.
They were. Frequently and at length. By me.

 Chris Lilley                    mailto:chris@w3.org
 Chair, W3C SVG Working Group
 Member, W3C Technical Architecture Group
Received on Friday, 23 July 2004 17:47:54 UTC

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