What Mack Brush says about their product...
The hair length in all three sizes is approximately the same – 1 1/4″ out. The Japan Brush is made with Black Goat Hair and a plain lacquered handle. Japans are great for painting backgrounds, especially glass backgrounds. They are great for pushing paint out of the way without leaving lines or streaks. The Japan Brush is also used for sizing large letters and objects. After you have gilded you can use the Japan Brush to brush off the ‘tails’. It will brush off without damaging the Gold Leaf. You can brush vertical, horizontal or diagonal and the gold will show the direction of the brushing, without damaging the surface.