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Re: [css-color] Safari 7 is color-managing CSS colors?

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Sat, 7 Dec 2013 16:07:50 +1100
Message-ID: <CAAWBYDA5_V-WpStdYJ7gf5K-u6x0tZzv9Yr+xZGhNYCJfYT7oQ@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: Dean Jackson <dino@apple.com>, Chris Lilley <chris@w3.org>, www-style list <www-style@w3.org>
On Sat, Dec 7, 2013 at 3:31 PM, Rik Cabanier <cabanier@gmail.com> wrote:
> Can you tell me where the color workflow is defined?
> For instance, it is defined that all CSS colors should be tagged with an
> sRGB profile. Image can optionally have a tag as well.

Not quite.  It's currently allowed for CSS colors to be unmanaged, if
untagged images are also unmanaged, and so they just get blasted into
the monitor's gamut without adjustment.  It's just tagged images that
have to be managed right now.

> How are those colors actually mapped when going to screen?
> I believe that in the case of Core Graphics, everything is drawn into a sRGB
> device which is then mapped to the output device.
> So, a tagged imaged would go: Image profile -> sRGB -> monitor profile.
> Assuming that the output device is properly calibrated, you would get the
> same colors everywhere.
>
> Is this how it's supposed to work? Or is a tagged image supposed to go to
> the monitor profile directly?

That's how it's supposed to work, yes.  Anything else is really bad,
because it means you're leaking color profiles all over intermediate
stages.

Colors should be treated like Unicode is.  Good hygiene means
converting bytes to codepoints as soon as they enter the system, and
not turning them back into bytes until they leave.  Same with colors -
bytes should be turned into a managed colorspace as soon as they
enter, and not turned into monitor profile until they leave the
system.

> Can you specify the rendering intent anywhere?

I don't think there's a need to?

~TJ
Received on Saturday, 7 December 2013 05:08:38 UTC

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