... a brush with tapered filaments.Natural bristle is the best choice for oil-based paints, varnishes, shellac, alkyd enamels, oil stains, and oil-based ... the smoothest finish with virtually no brush marks.Bristle is not recommended for latex or acrylic paints because it will absorb up ... , so it’s best to choose a synthetic brush for paint rough surfaces—even when using oil-based paints. oil/paint/varnish ...