Oil & Acrylic Oil Painting and Acrylic artists use hog bristles with flat square ends on wooden handles. When manufacturers discovered artists preferred old worn brushes they started making a type of brush called ‘filbert’ that is flat, but rounded on the end. Many professionals prefer this type. Newer synthetic brushes are becoming popular for their durability and ‘crisp’ paint application. Artists usually have several brushes in various sizes from small through medium to large.