What paint to use?

I want to decorate my harp with some scrolls and leaves on the soundboard. The finish is shellac with estopol over the top.

What sort of paint should I use? I was going to use acrylic.

Thanks!

Acrlylic over shellac and estopal doesn't seem right to me. A good quality artists oil paint would be my preference in that situation. They have richer pigments and will produce a much better glaze than plastics. You may only need the primary colours plus say an umber and a white if you're that way inclined and in small tubes they're not that expensive. You may also need a painting medium if you don't like waiting for the oil paint to dry, happy harping.