Exquisite 140 lb. (300gsm) professional watercolor paper made on a cylinder mould machine using 100% cotton and with natural woolen felts which give it a distinctive random texture. The surface is sized to make it strong and resilient to scrubbing, scraping and other rough techniques. Manufactured to high archival standards, each sheet is buffered with calcium carbonate to help defend finished pieces of work from discoloration caused by acids present in atmospheric pollution.