Which is better, varnish leather first and then paint, or paint directly on the leather? ?

Just have a small leather keychain, and I wanted to paint something really small on it.Which is better, varnish leather first and then paint, or paint directly on the leather? ?
Are you using acrylic? Your leather could soak up a lot of paint depending on the finish of the leather and the consistency of your paint. If your sure the paint will bond with the varnish surface, then you could varnish the are your painting to prevent too much absorption, then paint, then varnish over the whole thing.