Try a gloss varnish or acrylic medium. The sheen level for satin varies a bit unfortunately, it can be semi-gloss but can even be semi-matt by our standards (something like the standard finish of acrylic paints for artists, e.g. this).Einion I hear what you say about the white dots on the eyes and it makes sense. I ve tried before a satin varnish but I didn't shIne as much as I wanted. Maybe it needed more coats.