Grumbacher Gainsborough 12 Bright Oil and Acrylic Brush Gainsborough is Grumbacher's signature line of professional oil and acrylic brushes, and has been regarded as one of the best brushes for generations. They are ideal for laying down thick paint where brush strokes are required. Their natural flags and interlocked construction preserve the natural curve of the bristle. Made with a seamless nickel plated brass ferule and superior quality Chungking hog bristle, these brushes are known for the