Some time ago Steve Purcell reported an issue with hex colour rendering on OS X (http://lists.gnu.org/archive/html/bug-gnu-emacs/2011-05/msg00077.html). While nothing was changed in Emacs, many OS X users apply a patch similar to this one https://gist.github.com/purcell/3858136 (an older version of the patch is used by homebrew) to get the desired behaviour. I wonder if we cannot finally include the aforementioned patch or conditionnaly allow the use sRGB colour via a build option (like —with-srgb).