ok the one second from left, the grey brown one,, that is the natural color of the rawhide,, it came from africa and was a scrap from a drum repair, just got lucky on that,, the drawing on that bow is ink,, an archieval ink pen from the art store with a flexible tip,,I did coat the rawhide with hide glue to bring out the color,,, then I sprayed it with poly,, not to natural,, but the sinew bows I like to waterproof the best I can, but something natural would work too,,,
the one on the right,, is ink and oil paint,, oil paint is a mix of linseed oil and pigment so a little natural,, I have not experimented with natural pigment very much, but I am sure it can be very beautiful,, I have the oil paint on hand so use that,,and sometimes sand over it to make it look older or distressed,,the colors look more rich to me than acrylic,, but a beautiful job can be done with acrylic,, I just prefer the oil,,