- From: Chris Murphy <lists@colorremedies.com>
- Date: Tue, 22 Jul 2008 07:16:44 -0400
- To: Dave Singer <singer@apple.com>
- Cc: W3C style mailing list <www-style@w3.org>
I agree that stating colors are sRGB is sufficient. Everything else is either confusing or obvious. Chris Murphy On Jul 22, 2008, at 3:57 AM, Dave Singer wrote: > > some quick personal comments... > > > Isn't it enough to say that all colors are in the sRGB color space? > Isn't it a tautology to say that they should be correctly displayed > (e.g. an ICC sRGB profile associated with them, and then they should > be correctly converted to the display color space)? It feels a bit > like saying that straight lines should appear straight on the > display...but at most, 3.1.1 should say basically like the sentence > above, and not go into details of how one displays sRGB values, > gamma correction, out-of-gamut color handling, etc. > > Is the HSL full-range (0-255 luminance) or video-range (16-235 > luminance)? This makes a BIG difference. > > > At 0:31 -0400 22/07/08, Chris Murphy wrote: >> I'm not sure what you mean by "handling out-of range or invalid >> values." Do you mean a JPEG or text that somehow has an encoded >> value for red greater than 255? I don't see how that happens in an >> 8bpc world. There simply isn't a place holder for a value greater >> than 100%. >> >> But OK, if that can happen (?), then yes instead of the browser not >> displaying the image or content, or crashing or otherwise dramatic, >> fine just say anything higher than 100% is only 100% and proceed >> normally. But I would not call this gamut mapping or clipping, this >> is error correction in reading the page document or image data. >> >> I see in the example RGB 300,0,0. Umm, 300 levels don't exist in >> 8bpc. 110%? Doesn't exist. To me this implies floating point where >> values can be greater than 100% and less than 0%. >> >> That sRGB 255,0,0 may be out of gamut for my display, but how is >> this even knowable? You send the color to a CMS and ask it "is this >> out of gamut or not?" It can be done, but why bother? Just send the >> value to the CMS and say "display this" and it does the best job it >> can. Whether it's in or out of gamut doesn't, in my view, need to >> enter into the equation. The gamut check is a feature in Photoshop, >> but it's not particularly useful in my view, so I guess I'm just >> confounded why in and out of gamut colors is even a relevant issue >> for the developer of a web browser. Tag the data, let the CMS do >> the rest. >> >> Chris Murphy >> >> >> >> On Jul 21, 2008, at 11:59 PM, L. David Baron wrote: >> >>> On Monday 2008-07-21 23:47 -0400, Chris Murphy wrote: >>>> That whole paragraph. >>> >>> So the normal behavior in CSS for handling out-of-range or invalid >>> values is to treat them as parse errors. Since device gamuts vary, >>> we don't want to do that here. So I think the spec needs to say >>> something so that it's clear that the colors specified should >>> somehow be mapped into the device gamut rather than dropped. >>> >>> Is there a more general term than "mapped" that you would prefer? >>> >>> -David >>> >>> -- >>> L. David Baron http://dbaron.org/ >>> Mozilla Corporation http://www.mozilla.com/ > > > -- > David Singer > Apple/QuickTime >
Received on Tuesday, 22 July 2008 11:36:40 UTC