(Excerpts from ART HARDWARE: The Definitive Guide to Artists’ Materials, by Steven Saitzyk © 1987)
A nonarchival board is made of unrefined or partially refined wood pulp, or from recycled paper products where the residual lignin content is greater than in cotton (1 to 2 percent). The term “nonarchival boards” also includes any board that cannot maintain a neutral or slightly alkaline pH, as well as any board with significant levels of metals like iron and copper, which can oxidize and stain. Boards that have colorant that can bleed, or that have an alum sizing, are also nonarchival.
In general, nonarchival boards are not safe as a permanent support for fine artwork, although some painters have had limited success in preparing such boards for fine artwork by coating both sides with an acrylic polymer before painting.
Cardboards or Ground-Wood Boards
This group of boards, which includes cardboards, chipboards, and upson boards, is made primarily from recycled paper products and ground wood. These boards are highly acidic and contain metals and petroleum products. They should not be used in the production, or the storage, of fine artwork.
Corrugated Cardboard that is ‘/e inch, or single weight (called single wall in the cardboard trade), is composed of three sheets of a heavy, chemically treated, ground-wood pulp paper commonly called Kraft paper (named after the Kraft, or sulfate, pulp process). Two of the sheets are separated and the third, which is in the middle, is formed in a corrugated shape. This type of board has great strength in one direction. It is weak when bent along the corrugation, which can be compensated for by gluing two sheets of corrugated board together with the corrugation running in opposite directions. This results in an inexpensive and lightweight packing material.
Double-weight, or double-wall, corrugated board consists of five sheets of Kraft paper, two outside, one center, and two corrugated. Although the double weight is considerably stronger than single weight, it is still vulnerable to bending along the direction of the corrugation.
The strength of corrugated board depends on the thickness of the Kraft paper used to manufacture it. The type of corrugated board most commonly found in art supply stores is the same used to make the average corrugated cardboard box. It is single weight and is 36″X72″.
Henri de Toulouse-Lautrec often used corrugated cardboard for his artwork, and today it is not uncommon for people to follow his example. However, the limited number of surviving pieces produced on this board have only endured because of extensive conservation and restoration, not because this is a viable support for artwork. This board should not be used in contact with fine artwork or in conservation framing.
Chipboard and Newsboard are names that are used interchangeably. This type of board is made primarily of recycled paper products and, consequently, contains a great variety of undesirable impurities from metal to petroleum products. This board is used as an inexpensive mounting and backing board in nonconservation framing. It is often oil-impregnated; mounting, therefore, can be difficult and is often impermanent.
The appearance of chipboard ranges from an uneven brown to a mottled gray. The single weight is 45 to 55 pt., and double and triple weights are commonly available in the size 32″ X 40″ and can be found in 40″ X 60″.
Stencil Board is also produced by the Kraft (sulfate) paper-pulp process and is impregnated with oil or wax to make it waterproof. This waterproof quality keeps the board from absorbing the water of a waterborne paint and buckling. It also prevents the paint from flowing under the edge of the stenciled image. This board is, however, totally unsuitable as a ground for fine artwork. Most stencil boards are just thick enough to qualify as boards (12 pt.). The sizes most commonly available are 18″ X 24″ and 24″ X 36″.
Coated, or Covered, Ground-Wood Boards
Mat boards, illustration boards, mounting boards, Upson board, and watercolor board are among the ground-wood, or recycled paper, boards that have a surface covering that is designed to meet specific needs. Some of these boards can be used interchangeably, such as mat boards and mounting boards, but none of them should be used in the production of fine artwork or its storage.
Upsonite®, which is commonly referred to as Upson board, is produced by Domatar Industries, Inc. Although Upsonite is made largely from the same materials as chipboard, it is lower in density and a bit lighter in weight. It is also available in a greater variety of thickness, size, and surface. It ranges from ‘/x to % inch in thickness (the point system is not used for this board because it is treated more as a building material for temporary displays than as an art material), and from 4′ X 8′ to 4′ X 12’ in size. Textured finishes are produced in pebble, smooth, and linen, as well as a waterproof variety for outdoor displays.
This board is used in the arts primarily for model buildings, such as sculptural or architectural models, and mounting photomurals. It is popular for theater sets, parade floats, and game boards.
Mounting Boards are chipboard covered with white paper. Inexpensive mounting boards are covered on both sides with a clay-coated paper and are intended to be used only for mounting, such as for dry mounting photos and posters.
The better grades of mounting board are covered on one side with a bond paper, or inexpensive drawing paper, which is durable enough to handle pencil and paste-up. This type of mounting board is often referred to as mechanical, paste-up, or graphic arts board. It is designed to be an intermediate step in quality between boards that work well only in mounting, such as the clay-coated boards, and an illustration board, which is designed for multimedia. Graphic arts studios and newspaper publishers use this board for layouts, paste-ups, and for the overall design of a project that will be reproduced by some printing process. Mechanical board is less expensive than illustration board, and its use can result in considerable savings, particularly when the board is used in large quantities. Conventional clay-coated boards do not work well with pen, marker, or pencil and will not stand up under the constant repositioning of material attached with rubber cement or wax.
Mechanical boards are widely available in single thickness, but doublethickness boards can also be found. Mounting boards are available in white and gray. Single weight is between 45 pt. and 55 pt., and double and triple weights are common. Common sizes are 30″x40″, 32″x40″, and 40″x60″, though sizes like 20″ x 30″ and 22″ x 28″ are available in some of the better grades.
Railroad Board is made from recycled paper and is clay-coated, or surfaced with white paper. This board is often made water resistant, to prevent buckling when waterborne paint is used or because of handling with wet hands. It is relatively thin as boards go, and its thickness is rated in terms of plys rather than points. The most common thickness, four-ply, is not standard, and it can range from 15 pt. to 20 pt. Also fairly common is six-ply, but virtually the only size it comes in is 22″ X 28″. The surface paper, which covers both sides of the recycled paper core, is only slightly refined. Railroad board is produced in white, black, and several lacklustre, dyed colors.
Poster Board is a thicker and slightly stiffer form of railroad board; six-ply and eight-ply are the common thicknesses. In addition to the 22″ x 28″ railroad size, poster board is available in 28″x44″. Poster board is covered only on one side with either white or colored paper. This board is used for show cards, picket signs, and display advertising.
Scratch Board is poster board covered with a white clay coating and a black-ink surface, which can be easily scraped away with a razor blade or a knife specially made for this purpose. When the surface coating is scraped away, the contrasting white clay layer is exposed. Art done on scratch board can resemble an etching or a woodblock print. This board is used primarily in the graphic arts to create images to be reproduced in various print media. Scratch board suffered in popularity in recent years and is no longer readily available.
Mat Boards are ground-wood boards with facings of decorative paper, metal foil, fabric, and simulated fabric, and as well as various textured finishes. The ground wood used in better-quality mat boards is from pulp where the tree bark and knots have been removed or at least avoided. Such impurities do not bleach or readily break down during processing and can show up in the bevel when a picture mat is cut. The reddish-brown appearance of particles from the knots can be a stark contrast to the bleached ground-wood bevel, making the mat a total loss.
Mat boards are used for decorative and display purposes in and out of a picture frame. Mats were originally developed to keep paper artwork from coming in contact with the glass inside a picture frame. Later, mats were further developed to add a decorative border to paper artwork. Because of the high acidity of most mat board, paper artwork often develops a brown stain when in close or direct contact with these boards. A yellow stain can develop in as little as six months on some of the more absorbent print papers use in fine artwork. After several years of contact, it is often quite noticeable on the surface of artwork near the exposed bevel of the mat. Today, the Crescent Cardboard Company has begun to try to remedy the formation of this brown stain by adding chemical buffers, such as calcium carbonate, to their boards. Accelerated aging tests performed on their mat boards show that the boards still have a pH of 7.3 after a simulated one hundred years. It began with a pH of 7.7, so the increase in acidity would be considered negligible. Despite the good showing in pH this board should not be considered a substitute for museum board. It is only a much needed improvement of the standard ground-wood mat board. It is also likely that distributors of this board, as well as art supply stores and picture framers, will take several years to turn over their inventories for all the new boards. Using buffers is merely a temporary solution that will only delay the problem because the buffer will eventually be exhausted as the ground wood ages and as the boards absorb atmospheric pollutants.
The most common size of mat board is 32″x40″ with a thickness ranging from 55 to 60 pt. Selected colors are available in boards of 40″ X48″.
Illustration Boards are made of ground wood and have drawing paper adhered to one side. If the paper is smooth, like a plate-finish bristol, it is called hot press; if it has some texture, it is called cold press. Watercolor boards are illustration boards that have either a rough drawing paper or a thin watercolor paper surface. Acrylic boards have a canvaslike textured paper. Linen texture and laid finish (a charcoal or pastel paper finish) are available with in white, gray, and colored surfaces.
These boards are designed to be used for production art where surface appearance and convenience are the only requirements. The rigidity of the board’s backing keeps the paper surface flat during and after use so that artwork will photograph without distortion. In addition, this kind of artwork often passes through many hands and, if it were not on board, it could easily be damaged. Fine artists have often recognized this convenience and have been fooled by terms like “100 percent rag surface” into believing that such boards are safe for fine artwork, particularly since it is not unusual to find high-quality paper used for the surface of an illustration and watercolor board. However, with the one exception of the Strathmore 100 percent rag illustration board, this refers only to the surface. The ground-wood backing makes all such boards, no matter what their surface, unsafe for fine artwork.
The common sizes of illustration board are 15″ X 20″, 20″ X 30″, and 30″ x40″. Boards of 40″ x60″ are manufactured but are difficult to find. Single-weight illustration boards range from 50 pt. to 60 pt. Many of the different surfaces are found in double weight and a few in triple weight.
Rag Illustration Boards
Rag, or cotton, illustration boards are on the borderline between nonarchival and archival. They do not fit the definition of archival because they are often highly sized with alum and are therefore acidic. A board that is 100 percent cotton, like the Strathmore 500 series illustration board, which is the industry standard, is not greatly affected by a slightly acidic pH, nor, for that matter, are most of the artists’ materials that would be used on it. In any case, this board is designed for use in producing fine artwork as well as graphic artwork and not for storing documents in archives or in protecting art in museum-style picture framing.
The 100 percent cotton illustration boards manufactured by Strathmore have a very durable surface and resemble bristol paper in their finish and working qualities when using various drawing materials and waterborne paints. Their greatest asset is their ability to stay flat under almost all conditions.
Cotton illustration boards are available in two weights-heavyweight, approximately 65 pt., and lightweight, approximately 33 pt. The lightweight with regular (cold press finish) surface comes only in 22″ x30″. The heavyweight in regular surface and high (hot-press finish) surface is available in 20″x30″ and 30″ x40″.
(Excerpts from ART HARDWARE: The Definitive Guide to Artists’ Materials, by Steven Saitzyk © 1987)