Product Description BINDER SKETCHBOOKS BY KUNST and PAPIER: The sewn and gauze-spliced bindings of the K&P make for a strong and durable sketchbook. This unique binding method allows the books to open flat and beyond without damage to the binding. The heavyweight acid-free paper is an excellent support for all dry media and is suitable for water-based markers and light washes. It is also pH buffered lignin and chlorine-free. On the outside, gray binders board covers are bound with linen spines. These distinctive spines are available in five different colors. The books themselves are available in a variety of popular sizes.