Cotman Watercolour Paper is an inexpensive, mould made, wood free paper with maximum stability. It's also acid free for extensive life without deterioration. Cotman has a natural warm whiteness and is both internally and externally sized. The sizing ensures even absorption, brilliance of colour, and easy erasing, sponging, and removal of art masking fluid without damaging the surface.These spiral bound watercolour pads each contain 12 sheets of 140 lb. cold press Cotman paper, with strong backing boards for added rigidity and stability.