I've heard Ryan Neal say that he mixes white paint with Lime sulfur for use on juniper dead wood. Do you know if it's water color or acrylic?
The old time So CAl bonsai crowd used to do the same. They used several things- gesso made for preping canvas's for paint, water colors and acrylics also some times india ink. I find the paint and gesso fill too much of the grain in the wood and don't like it. I think it gets more then white enough just using lime sulphur.
I seen koji hiramatsu Japanese bonsai master Use a mix of white and just a dab of black acrylic paint. To seal the deadwood on a shohin. Juniper. I think it looks very good. But I think he used rather then lime sulfur because it put it on a right away and the paint somewhat protects the tree. After doing extensive work in a short time …. Attached is some pics. From the article bonsai empire