An even and short buffing nap is achieved by a retannage with Syntan HO. Syntan HO does not bleach the leather colour. It distributes the dyestuffs evenly in the grain area. This results in a uniform colour of the buffed surface. Including Syntan HO in the retanning improves grain tightness. Syntan HO prevents over-plumping of the leather when larger quantities of filling products are used. It prevents excessive strain on the fibres and reduces stretch. Syntan HO improves the flatness and smoothness of the grain.