Elizabeth T. Gilbert - Artist Toolbox: Surfaces & Supports

Material The majority of paper today is made out of cellulose fibers derived from wood pulp, cotton, or a blend of the two. Generally speaking, the higher the cotton content, the higher the paper quality. Papers made of 100-percent cotton are more durable and less likely to become brittle or yellow over time. Papers made from cotton rags are called rag paper; these strong sheets are made up of the longest cotton fibers. However, most cotton paper is made of cotton linter (shorter fibers) or a combination of rag and linter. Wood pulp paper is more affordable than cotton paper, and modern techniques for reducing the acid content make this option more appealing to artists.

Some papers are manufactured with an ingredient called sizing or size. Sizingwhich is usually gelatin or animal gluechanges the way a paper accepts a medium. The more sizing a paper has, the less likely it is to absorb moisture and pigment. Papers made specifically for ink or marker often have a good amount of internal sizing, which means that the sizing is mixed in with the pulp before the paper dries. This makes the ink less likely to bleed through or across the paper while keeping the color vibrant. Many watercolor papers are also coated with surface sizing, giving the artist control over the washes. (See Sizing, .) Sizing also keeps the paper from buckling under moisture.

Weight Paper weight is measured in either pounds (lb) per ream (500 sheets) or grams per square meter (gsm or g/m2). The measurement system of pounds depends on a sheets size and varies between paper types, so there is no across the board conversion method for matching lb. and gsm. Using gsm to describe a papers weight is more consistent and perhaps more descriptive; however, the pound system is more common in the United States. Below are some of the most readily available paper types and weights, listed in both lb and approximate gsm. Remember: The greater the lb or gsm, the thicker the paper.

RAG PAPER IN ACTION

Aside from art, rag paper is used for important documents that need to last or withstand wear and tear. Paper money, which endures plenty of abuse and folding, is made of rag paper.

STANDARD PAPER WEIGHTS