Q: Is it best to create small skinny tree branches with the paint thinned with oil (like walnut or linseed) or with something like mineral spirits?
A: Actually, I don’t use any thinner when painting branches. Generally I like to use paint straight from the tube without any medium because the branches have nicer edges that way.
When medium is used the paint flows together and blends, and the branches take on a sameness that I find less interesting. Plus, the edges tend to be sharper and less natural feeling with thinned paint.
Here’s a quick example of the fun details you can get from straight paint:
I will often push the front edge of a flat brush forward into a pile of barely mixed paint and then apply it with a stroke that gently pulls the paint off the brush edge.
Don’t you think that results in a much more interesting broken color branch?