When choosing the weight of a fine art paper, what is more accurate, lb or gsm?
There are two ways to measure a paper’s weight. The North American way is to weigh 500 sheets of a common size of paper (such as 8-1/2” x 11”) to come up with a lb measurement. This measurement isn’t consistent across different types of paper, however. GSM stands for Grams per Square Meter, a metric (or European) measurement that is a more consistent method for measuring different paper types. When using this method, one sheet of any paper, regardless of type, weighs one square meter. Therefore, if you’re comparing the weight of a watercolor paper to a drawing paper, look at the gsm and not the lb.
What are the most common types of art paper?
Cotton papers, made from the longest cotton fibers, are generally considered the highest quality. Paper made from 100% cotton rag can handle heavy working and erasing without tearing or showing wear. High-quality 100% cotton paper can last more than 100 years. Those papers made from shorter, lesser-quality cotton fibers can become fuzzy with reworking. Cellulose papers are usually made from wood pulp and have a natural acid content that will destroy the paper over time. The more acidic a paper is, the shorter its life expectancy. Buffers are often added to make a cellulose-based paper pH neutral and extend its life.