Hello, A while back, there was an effort to add support for true-color terminals (by which I mean terminals supporting 16777216 simultaneous colors): http://emacs.1067599.n5.nabble.com/RFC-Add-tty-True-Color-support-td299962.html I've contacted Rüdiger, asking if he wouldn't mind if I pick up from where he left off, and he said that was fine as he's been too busy to work on this. I've attached to this email the patch that I'm using, based on his work. Any feedback would be greatly appreciated. This is my first (attempted) contribution to Emacs, and I'm very new to the code base, so there might be some silly mistakes that I'm unaware of. If we can get this polished enough for inclusion, I'd be more than happy to assign copyright. This patch is based off of Emacs 24.5. If it would be easier to get this merged into Emacs 25, I can rebase my changes and submit a new patch for review. Thanks, Charles