I use Fiebings leather dye, it comes in all colours. I usually do a tan base then stripe it to resemble curly. I just did one with black over red and rubbed the black off early so the red showed through to match the burgundy latigo sheath I made for the hawk. I'll take a pic tomorrow if it stops snowing here and post a link to it. You can buy the dye at Tandys if you are near one. Shoe repair shops usually carry the black too.
Regards
Robin