From njs@uclink4.berkeley.edu Thu Mar 14 21:05:22 2002 Return-Path: X-Sender: njs@njs.ddts.net X-Apparently-To: lojban@yahoogroups.com Received: (EGP: unknown); 15 Mar 2002 05:05:21 -0000 Received: (qmail 90477 invoked from network); 15 Mar 2002 05:05:21 -0000 Received: from unknown (216.115.97.172) by m11.grp.snv.yahoo.com with QMQP; 15 Mar 2002 05:05:21 -0000 Received: from unknown (HELO WyrmWeyr.frop.org) (169.229.89.124) by mta2.grp.snv.yahoo.com with SMTP; 15 Mar 2002 05:05:21 -0000 Received: from njs by WyrmWeyr.frop.org with local (Exim 3.33 #1 (Debian)) id 16ljtt-00014f-00 for ; Thu, 14 Mar 2002 21:05:09 -0800 Date: Thu, 14 Mar 2002 21:05:08 -0800 To: lojban@yahoogroups.com Subject: Re: [lojban] color Message-ID: <20020315050507.GA3874@njs.dhis.org> Mail-Followup-To: lojban@yahoogroups.com References: <200203150318.WAA18081@mail.reutershealth.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200203150318.WAA18081@mail.reutershealth.com> User-Agent: Mutt/1.3.27i Sender: Nathaniel Smith From: Nathaniel Smith X-Yahoo-Group-Post: member; u=29848869 X-Yahoo-Message-Num: 13776 On Thu, Mar 14, 2002 at 10:17:29PM -0500, John Cowan wrote: > Jay Kominek scripsit: > > > x3 is exactly what you're asking for. Yes, RGB is borked, but I believe it > > still makes an acceptable default, as most people are familiar with it, > > and do not need the kind of precision required. > > What's wrong with RGB at gamma = 1? There are two main problems: 1) No precision. Every monitor in the world has a different space called "RGB", and the same RGB triple can look very very different on different devices. (Fixing gamma does help here, somewhat, but not that much -- there are still differences in phosphors, etc. And let's not get into environmental lighting conditions...) 2) Poor gamut. There are lots of colors which aren't expressible using RGB (at least, not without serious cheating). This includes all the most intense (saturated) ones. Nice picture (look for "gamut"): http://www.adobe.com/support/techguides/color/cms_glossary/G.html (The solution to both of these problems is to use one of the CIE spaces, like CIEXYZ or CIEL*a*b* or CIEL*u*v* or ... These spaces often tend to be "more intuitive" as well, ie, correspond more closely to perceived color.) These problems, of course, are likely irrelevant to this discussion :-). (Though, honestly, I can't imagine that people will ever use this selbri aside from describing how to set a web-page background or something. Most color space coordinates really aren't intuitive -- if you don't believe me, then quick, what's the difference between tan and brown in RGB? And what are the coordinates for purple? Would you be able to answer questions like that usefully while half-way through a sentence?) -- Nathaniel -- So let us espouse a less contested notion of truth and falsehood, even if it is philosophically debatable (if we listen to philosophers, we must debate everything, and there would be no end to the discussion). -- Serendipities, Umberto Eco This email may be read aloud.