When I first decided to get back into producing art I stood in the store in the paper aisle totally bewildered by the choice available. All the different papers were a mystery to me and the terms even more so. I really didn't know what the differences were or how to make my choice. I stumbled around and made some bad choices in the beginning. I have since learned a lot about paper and how to choose the best kind for the project I have in mind. I found the following descriptions and they are very helpful if you are just beginning and find yourself as confused as I was. These terms are also helpful if you are buying art as most artist refer to these terms in their listings.
Acid Free Paper - Acid free papers are buffered with an alkaline reserve, such as calcium carbonate, to neutralize acid compounds absorbed from the atmosphere or formed through natural aging.
Archival Paper - Paper manufactured to provide the ultimate resistance against natural aging. The most important characteristics are: no groundwood or unbleached pulp, a minimum pH of 7.5, and additional alkaline reserve of 2%.
Basis Size - Sizes based on traditions/customs which represent the industry standard for a specific paper grade. For example, the basis size of watercolor paper is 22" x 30".
Basis Weight - The weight in pounds of a ream (500 sheets) of paper in a given size. A 140 lb. watercolor paper will be one in which a ream of 22" x 30" sheets actually weighs 140 pounds. For comparison typical copy paper is 80 lb. For Watercolor the heavier the paper the better as it absorbs more water. I do not like to use any less than 140 lb paper as the finished product is not as desirable. A 300 lb paper gives beautiful results.
Bristol - Artist Bristol generally describes drawing paper that is pasted. Two or more sheets are pasted together to form 2-ply, 3-ply, etc. Sheets are pasted into Bristol to achieve stiffness, strength and to form a sheet with two identical useable (felt or top) sides.
Cold Press - A term used to describe the medium surface of certain textured paper used for watercolor work. This is my preferred choice as the surface is slightly rough and it absorbs water well.
Picture is on 140 lb, cold press paper. Medium used is watercolor pencil.
Felt Side - The side of paper known as the “top side,” it is considered the preferred working side of a sheet of paper.
Grain Direction - The direction in which the majority of fibers lie in a finished sheet of paper corresponding to the direction the wire travels on a papermaking machine. Handmade papers have no grain direction.
Hot Press - Used primarily in describing watercolor papers with a very smooth surface. This type of paper doesn’t absorb the watercolor as easily as cold press.
Lignin - An organic substance which acts as a binder for cellulose fibers in wood and certain plants, adding strength and stiffness to cell walls. Lignin is undesirable in the production of fine, permanent papers because it reacts with light and/or heat to produce henols (alcohols) and acids, which cause deterioration and embrittlement of the paper. Choose lignin free paper for your artistic endeavors.
Mould (Mold) Made - Although originally describing a handmade process, today “mould made” papers are produced on a Cylinder machine. Cylinder machines differ from Fourdriniers only in the way the pulp is applied to the wire.
Rough Surface - A term used to describe a coarse, textured paper. Often used by artists when discussing the surface characteristics of watercolor paper.
Smooth Surface - A paper with a very smooth, hard finish. Ideal for pen and ink, marker, airbrush and mechanical layouts.
Vellum Surface/Medium Surface/Regular Surface/Kid Surface - A term used to describe the finish of a sheet of paper, with a minimum to moderate tooth. Ideal for pencil, charcoal, airbrush, pastel, crayon, and pen and ink, (not requiring a solid line).
Watercolor on 140 lb. Cold Press Paper