Designed for use with watercolor, gouache, pen and ink, acrylics and calligraphy, this Arches pad is a versatile addition to your studio. Use it with virtually any medium, so you're able to paint, draw and sketch, all in the same pad. Watercolor block helps minimize the need for stretching. Mould-made paper is acid free, chlorine free and made of 100% cotton fibers for extra strength and stability. Paper is tub-sized in natural gelatin and air-dried. Resists scrubbing, scratching and erasing while keeping the original intensity of the watercolor. Each block consists of pre-stitched sheets of paper that are glued together along all 4 edges and supported by a rigid backing. The top sheet is easily separated from the block by inserting a knife under the sheet and running it around the edges. No optical brighteners are used. Natural white color will not yellow with age. Arches(R) Aquarelle Watercolor Block, 140 Lb, Hot Press, 12in. x 16in. is one of many available through Office Depot. Made by Arches.