RE: Color Management in HTML5?

Does it explicitly say that in the Canvas spec?  Is a Canvas-supporting UA required to support all colorspaces of all standard image formats?  For example, JPEG supports CMYK (both with and w/o profiles).  Should I expect all UAs to support that?  Only some?  What profiles are supports - only level 2 or level 4?  What rendering intent(s) are chosen - and how are they specified by the author?  Is BlackPointCompensation used  and can the author specify?

I am not necessary expecting answers to these questions - I am raising them here to point out some of the myriad of issues that are involved in proper color management and specification of UA behavior for same.

I hope that we can all agree that users (and especially commercial vendors displaying their products online) are going to be unhappy when their colors don't display properly.  Thus, this seems like an issue that needs to be addressed.

Leonard

From: Frank Olivier [mailto:franko@microsoft.com]
Sent: Saturday, March 06, 2010 1:43 AM
To: Maciej Stachowiak; Leonard Rosenthol
Cc: public-html@w3.org
Subject: RE: Color Management in HTML5?

>From my interpretation of the canvas spec: canvas is always in device color space. A canvas.DrawImage(tagged image) call should convert colors into the device color space.

From: public-html-request@w3.org [mailto:public-html-request@w3.org] On Behalf Of Maciej Stachowiak
Sent: Friday, March 05, 2010 12:09 AM
To: Leonard Rosenthol
Cc: public-html@w3.org
Subject: Re: Color Management in HTML5?


On Mar 4, 2010, at 10:24 PM, Leonard Rosenthol wrote:

I am sitting in a meeting of the ICC (International Colour Consortium) and the question about whether (or how) HTML5 address colour management issues came up. So I did a quick search of the current draft of the document and the ONLY reference I could find was that color specifications are in sRGB.  No mention about profiles in images, etc.

Is this indeed the case?  Has any consideration been given to richer color management of data (esp. images) present in HTML5 documents?

If not, is there any reason that the ICC could not present a Change Proposal to introduce requirements for UAs in this manner?

Most color management issues on the Web are not in the domain of HTML5. Color management of CSS colors (e.g. colors use for text, background colors, border colors, etc) is an issue for CSS. I believe there is a proposal to allow CSS colors from an arbitrary colorspace to be used. Nominally, CSS colors are in the sRGB colorspace by default.

Color management of images is an issue for the image format specs and/or a quality-of-implementation issue.

Color management of video is up to the video format specs and/or a quality-of-implementation issue.


Just to report on what Safari does: we colormatch images that are tagged with an explicit colorspace, but we treat CSS colors and colors in untagged images as being in the device color space (instead of treating as sRGB). This seems to give a good balance between performance for the common case and color-correctness for cases where precise color is desired.

Regards,
Maciej