We paint on a variety of leather types;  goatskin, buffalo, cowhide, deer hide, horsehide, pigskin, etc.   We have even painted designs to MA-1 (nylon) jackets, microfiber, and denim.     Different leathers accept paint differently, and thus we prep  surface areas prior to painting to ensure the best adhesion. We do not paint to suede, as the nap of the leather is too long to effectively hold paint. We also do not recommend painting to faux leather surfaces (synthetic/plastic), as plastic out-gasses and eventually lifts the paint.