BOARDS

THE FIRST STEP in discussing any paper  board  is  to define a board. A paper board is defined by its  thick­ ness. Any paper that is 0.012 inch or more, which is a little less than 1/64 inch in thickness, can accurately be called a board. Tissue paper is approximately 0.001 inch thick, bond paper ranges from 0.003 to 0.004 inch, and one-ply museum board ranges from 0.0125  to  0.015 inch. The material most commonly used to store and protect fine art is four-ply museum board and its thick­ ness ranges from 0.050 to 0.060 inch (0.060 inch is almost 1/16th of an inch.

 

At one time there were several ways to define various boards by their thick­  ness. A standard mat board  was said  to  be fourteen-ply  (roughly  the equivalent of putting together fourteen sheets of bond paper) and double-weight mat board twenty-eight-ply. A standard museum board, which is approximately equal  to a mat board in thickness, is called four-ply because each ply is much thicker than bond paper and it takes only four to reach the desired thickness. Today, most manufacturers of paper boards are shifting toward using a point system of meas­ urement, which will make it easier to comprehend thickness and to  compare various boards. In the point system,  one  point equals  0.001 inch.  Therefore,  if the average mat board or museum board is between 0.050  and  0.060  inch  it would be between 50 pt. and 60 pt. in thickness.

There can often be as much as a four-point variance of thickness within a manufacturer's advertised thickness. Manufacturers of mat board have,  for  the most part, dropped their system of defining thickness by  plys  in favor of  the  point system. Some manufacturers who make both mat board and boards for illustration, as well as for graphic arts, refer to their 50 pt. to 60 pt.  boards  as single weight, and their 100 pt. to 120 pt. boards as double  weight.  Museum boards are still most commonly referred to in plys, although the point system is rapidly taking over.

The type of board is defined by its content, such  as  ground-wood  boards, which, regardless of whether or not the surface is rag, are for graphic art use or other nonfine artwork. Boards that can be used in archives, such  as  museum board, are composed of rag, cotton, or purified cellulose. In the case of foam­ centered boards, the center is composed of styrene. In the following entries there are explanations of the composition of  the various  boards and the reasons  they  are made the way they are, as well as indications of  the  circumstances  under which they can be used with fine artwork.

 

Nonarchival Boards

 

 

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 ¼ 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  bend­ ing 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

 

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art supply stores is the same used to make the average corrugated  cardboard  box. It is single weight and is 36" x 72".

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,  con­ tains a great variety of undesirable impurities from metal to petroleum products. This board is used as an inexpensive mounting and backing board in nonconser­ vation 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" X40" and can be found in 40" X60".

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 com­ monly 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  mate­ rials 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  1/s  to 3/s 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  mate­ rial), and from 4' X8' to  4'  X12'  in  size.  Textured  finishes  are  produced  in  peb­ ble, 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 mount­ ing boards are covered on both sides with a clay-coated paper and are intended

 

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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,  pasteups,  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  double­ thickness 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" X 40", 32" X 40", and 40" X 60", though sizes like 20" X30" and 22" X28" 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" x 44". 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 popu­ larity 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

 

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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 pic­ ture frame. Mats were originally developed  to keep  paper artwork  from  coming in contact with the glass inside a picture frame. Later, mats were further devel­ oped 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 per­ formed 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 tum 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" x 40" 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 illus­ tration 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.

 

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The common sizes of illustration board are 15" X 20'', 20" X 30", and 30" X 40". 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 quali­ ties 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, approx­ imately 65 pt., and lightweight, approximately 33 pt. The lightweight  with  reg­ ular (cold press finish) surface comes only in 22" X30". The heavyweight in  regular surface and high  (hot-press finish)  surface is available in  20" X 30" and 30" X40".

 

Archival

Boards

 

 

AN ARCHIVE is a place to keep records. Archival refers to something used  in  storing and preserving such as archival boards, which are used for storing and keeping artwork and records. The qualities that make a board safe for storing artwork and valuable documents have been evolving since the mid 1970s.  The most desirable board is one that does not age, remains  at a  pH of  7,  is totally inert, is iron- and copper-free, is inedible to insects, remains free of mold and mildew, does not condense moisture,  yet is absorbent.  The development  of  such a board is unlikely for many years. A more reasonable expectation  for an archi­  val board would be that it is composed of either 100 percent purified  cellulose from wood or 100 percent rag  (or cotton)  fiber and that it is at least  50 pt. thick.  It should also be free of iron and be buffered to remain free of  acid for seventy­ five to one hundred years under normal framing and storage conditions.

The logic for this is that a board made from cotton, rag, or purified wood cellulose is relatively inert, does not readily  condense  moisture,  and is practical  in that it can easily be cut to size. The thickness is important because it provides both a mechanical and a chemical barrier.  Thicknesses  of  less than  50 pt.  may not be sufficient to keep a moderate-size piece of art (26" x 36" or larger) away from the glass facing when it is framed. This is important because there is  a  natural tendency for artwork that is hinged to a mat, rather than  glued  to  a backing, to curve toward the glass (see Framing  and  Storage,  pages  275 to 307, for more information). Boards of less than 50 pt. are more easily subject, with changes in humidity and temperature, to developing buckles that can be trans­ ferred to the artwork that is being stored or framed. The same thickness is also needed to provide a chemical barrier from the acids present in polluted air and  from such other storage materials as the backings used in framing or the wooden file drawers used for storage. Buffering of the board is mandatory, with the exception of boards made for the storage of albumin,  dye  transfer,  and Cibachrome prints so that any acids from the storage environment and air pollu­ tion can be neutralized. Care must  be taken  by  the manufacturer  to be certain  that there is no residual iron in the board that may accumulate  in the washing  of the fibers during processing.

Any  board that can  meet these requirements  and show  no detectable deteriora­

tion for seventy-five  to one hundred  years  should  be considered  safe and proba-

 

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bly would remain safe for several more generations. The type of museum board currently in use has not been around for one hundred years, and all claims to permanency are based on theory and accelerated aging tests. In other words, everyone is attempting to make the best decisions possible with whatever infor­ mation is currently available. It can be expected that new definitions and  mini­ mum requirements will continue to evolve.

MUSEUM BOARDS

"Museum board" is the common name for  100  percent  rag  or  cotton-fiber  boards that meet the current minimum  standards  for  archival  use.  Museums  were  among the first major users of this type  of  board  for  storing  and  framing  artwork,  hence the name. At one time, this board was also called  rag  board.  Because  there  are several types of boards that contain rag or cotton that do not meet the minimum standards for archival use, the name has slowly been replaced. Despite the  intro­ duction of conservation boards composed  of  purified  wood  cellulose,  museum boards are  still  overwhelmingly  the  board  of  choice  for  archival  purposes,  because rag or cotton fibers are longer  than  those  of  purified  wood  cellulose  and are, therefore, stronger and  more  durable.  Any  picture  framer  knows  that  it  is much harder to c_ut a mat from  a  museum  board  than  a conservation  board,  and that cutting blades wear twice as fast when cutting a museum board.

Several manufacturers produce a limited selection of colored museum boards. The Strathmore Paper Company, for example, manufactures two grays, five col­ ors, black, white, natural, and cream, all tested for bleed resistance, scuffing, rubbing, and abrasion to meet standards established  by the United States Library  of Congress. The thickness of its four-ply boards was originally between 50 and

55 pt.; however, Strathmore has increased it to 60  pt.  to  compete  with  the thicker boards now on the market. Museum board of  a  one-ply  thickness­ between 12.5 and 15 pt.  and  usually  available only  in  white-is  used  primarily for temporary storage and as a separation sheet when stacking artwork. It is also occasionally used as a drawing paper.  Museum  board  that  is two-ply  can often be found in the same range of size and color as that of four-ply, and is used for temporary storage for up to twenty-five years. It is too thin to be used in picture framing as either a mat or a backing. Both one-ply and two-ply are available in only 32" X40".

Museum board that is four-ply is most commonly used  for long-term  storage and museum-style framing. It is available in various shades of white and gray, as well as a limited range of colors, in 32" X40", and is also made in 40" X60". A new, still larger size, 48" X84", has begun to be distributed in some major cities. New and not readily available, six-ply and eight-ply are, in most cases, chosen more for aesthetic reasons in picture framing than for additional protection.

RAG MAT BOARD

Rag Mat is a 100 percent rag board with a buffered, fade-resistant, colored, sulfite-pulp paper facing. It is produced by the Crescent Cardboard Company. It

 

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is currently manufactured in twenty-eight colors, and new colors are soon to be introduced. The boards are available only in 32" x 40''.

The early versions of this board had a thickness  of  approximately  45  pt., which was considered by many people to be too thin to keep most medium-size paper artwork away from the glass in picture framing. These boards  are,  how­ ever, being replaced with ones that are 50 pt. Rag Mat "100" is similar to the Strathmore museum boards, which are now produced in a thickness of 60 pt. in four-ply.

CONSERVATION BOARDS

These boards are made neither from rags nor from cotton, but are composed of purified cellulose pulp from wood where the lignin has been  removed  and  to which an alkaline buffer has been added. Conservation boards are  made to meet  the same requirements as those for museum boards, and are accepted by most institutions for use in archives. Some conservative conservators still question this type of board for long-term use because  of  the  extensive  chemical  processing that the fibers undergo. They believe that the fibers are significantly weakened, affecting durability and possibly even permanency.  Nonetheless,  as rag and cot­ ton fibers become increasingly rare and expensive, conservation  will  become more common.

A large percentage of conservation boards  available  at this time  are produced by three companies-the  Rising  Paper  Company  produces  Conservamat, Andrews Nelson & Whitehead offers pHase 7, and the Process Materials Corpo­ ration offers Archivart Conservation Board. With the exception of the white and cream produced by the Process Materials Corporation, these boards are  all between 50 and 60 pt. in thickness and 32" X40" in dimensions. Larger  and  thicker sizes are not generally available.

The color selection of conservation boards is much the same as the limited selection of museum boards, although black is not available.  At  one  time,  the gray pHase 7 boards used for framing changed significantly after a year or two, becoming lighter and developing a red tint. Today, primarily due to intense com­ petition, most manufacturers apply stringent tests to avoid such problems as fad­ ing. These tests, however, are accelerated aging  tests,  which  only  simulate certain aspects of the aging process and therefore cannot  be  a  substitute  for actual conditions.

The leading conservation mat board, Alphamat, made by the Bainbridge Com­ pany, is the conservation board equivalent to Crescent Cardboard's Rag Mat. Alphamat is available with paper facings in sixty colors, which are pigmented to prevent fading. The board itself is a bright white. The  bright  white  bevel, although eye-catching  on white and off-white  mats, is found by many people to be distracting on the darker and more strongly colored  shades  of  mats.  This  board is designed for use in picture  framing  where the artwork  is not  touching  the paper facing. Although several pastelists have used  this  board  surface  to  draw on, it is not clear  whether  it is generally  safe for fine  artwork.  The surface is a very thin paper adhered to an archival board and this combination  would appear to be less hazardous than using a colored wood-pulp paper alone because,

 

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over the years, as the paper facing loses its strength,  it  has  the  board for sup­ port. In addition to the sixty colors available in 32" X40",  nine are produced  in  40" x 60'', but are not readily available. The boards are 55 pt. thick.

 

ARCHIVAL NONBUFFERED BOARDS

Albumen photographs, which were made through an early method of producing black-and-white prints with animal protein, and  dye transfer  prints,  produced  by a more modem and lightfast method of  producing  color  prints,  are  both adversely affected by an alkaline pH, or a pH of more than 7.5. Dyed  natural fibers, like silk and wool,  are also sensitive  to alkalinity  because  the dyes  used in their production are usually acid dyes. It is therefore best to avoid buffered museum and conservation boards when framing albumen photographs, dye trans­ fer prints, and work made of natural fibers.

Nonbuffered archival boards are very specialized, and are not readily  availa­ ble. The  Light Impressions  Corporation,  however-a  mail order  house  that sells  a large variety of archival supplies to the public as well as to the trade-offers a

50 pt., four-ply, 100 percent rag board that is not buffered, in sizes from 811  x 10" to 32" X40".  The  company's  address is: 439 Monroe  Avenue,  Rochester, New York 14607.

 

ARCHIVAL CORRUGATED CARDBOARD

The Process Materials Corporation produces a buffered corrugated board that appears identical to ordinary corrugated board, except that  it  is  blue-gray  or bright white rather than brown. It is called Archivart Multi-Use Board, and is available in both single weight (single wall), 1/s-inch, and double weight (double wall), ¼-inch in sizes of 32" X48", 40" X60", and 48" X96".

Archival corrugated cardboard is used as a backing board in museum-style framing and storage, as well as an artists' material. Although the purity  of  the wood pulp used to make this board is questionable, as is the quality  of  the adhesive used to hold the various layers together, the  manufacturer  claims  it meets archival requirements. For additional security when  using the board as an  art material, I have had good results in creating rigid, and safe,  painting  surfaces by mounting 100 percent rag to this board.

Foam, or Foam-Center,

Boards

 

FOAM BOARDS were originally developed for use in the graphic arts, but have now found their way into the world of fine art. Foam-center boards  are light­ weight boards made of a rigid plastic foam with a paper or plastic facing. They resist warping, are more dimensionally stable than boards made from wood pulp, and are far less acidic. Despite the many advantages of this type of  board  over most paper boards, it cannot be considered archival because the core is poly­ styrene, or some variant of polystyrene, and this material naturally  decomposes over a long period of time and is said to give off  acid vapors.  This aging  process is greatly accelerated when exposed to ultraviolet  light  (some  of  the  newer boards have UV stabilizers) and  air  pollution.  Some  manufacturers  have  begun to buffer the surface paper to help maintain  an acid-free  surface.  In museum­  style picture framing, where foam board is used as a backing material, it is not exposed to ultraviolet light and the elements. This would make its use in framing quite safe as long as it is not in direct contact with the artwork.  Unfortunately, some artists think this material is safe to  use as a  painting  or sculpture  material for fine artwork when they learn it is  used  in  museum-style  framing.  Unless foam board is thoroughly covered-particularly the exposed foam  edges-with enough paint to seal the surface from air and to  prevent  ultraviolet  light expo­ sure, it will deteriorate too rapidly for fine art.

 

FOAMCORE BOARDS

Foamcore boards are made with a polystyrene core and either  a  white  clay­  coated or brown Kraft paper facing. The original white foamcore board was produced for the graphic arts industry by Monsanto and was named Fome-Cor. Today there are several other competitors, as well as a generic version. The way  the polystyrene bubbles are formed during manufacture allows the edges to stay sealed, or at least crimped, during die cutting.  This  creates  a characteristic  pil­ low effect. It also means that any accidental impressions or dents  can  perma­ nently damage the board. The foam center is not affected by moisture, but the surface paper is, and outdoor use as well  as  wet  mounting  can  be a  problem.  The surface will readily accept oil paints and acrylic paints, but the foam is  sensitive to some solvents, particularly those in lacquers and shellacs. Fome-Cor

 

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cuts easily with a razor blade, if the blade is sharp and  without  defects;  if  it is  not, it can tear the foam instead of cutting it. My experience with this particular board is that it behaves as if it had a grain and tends to cut well in only one direction. This board is commonly used in dry mounting  and  vacuum  mounting, as well as in wet mounting when counter mounting is done (see Framing and Storage pages 287 to 295).

There are three types of Fome-Cor:--0riginal, acid-free, and super thick. The

original is made in two thicknesses, %  and  3/i6 inch,  and four sizes,  20" X40", 32" X40", 40" X60", and 48" X96", of which the first two are  most common.  In the 3 1i6 -inch thickness, there is a greater variety of available sizes, but only the first three are readily  found.  The surface  pH is slightly  acidic, 5.5 to 6.5,  and it  is for this reason Monsanto produces an acid-free Fome-Cor where the surface paper is buffered to a pH of 7.5 to 8.5. The printed literature for  this  board suggests that it is archival and may be used  as a substitute  for museum  board. This seems questionable because, for example, the surface of this board is made from a Kraft paper and not a purified cellulose,  or cotton  fiber.  It is  uncertain how much alkaline reserve the buffer can provide in  neutralizing  air pollutants  and the natural formation of acid during the aging of Kraft paper. There are also questions about the permanency of polystyrene itself. This board is obviously an improvement on the original; nevertheless I have reservations about its archival qualities. The acid-free foam core is produced in thicknesses of % and 3/i6-i nch, and sizes of 32" X40" and 40" X60". The super thick  variety,  called  Fome-Cor ST,  is  identical  to  the  original  board  but  is  ¾-thick   instead   of   3/16 -inch  .   The available sizes are 30" X40", 32" X40", and 40" x 60".

 

PRIME-FOAM-X® BOARD

Prime-Foam-X is produced by Primex Plastics Corporation. With all its sim­ ilarities to Fome-Cor, it has some significant  differences.  The outer paper  facing is thicker, whiter, and glossier. The formation of the foam  bubbles  and  their higher density in this board allow for better retention of shape and minimize damage. This board is said  to have  "memory"  because  slight  indentations  tend to heal themselves.  Consequently,  in die-cutting  the edges do not  crimp or seal  as they do with Fome-Cor. I have found that Prime-Foam-X does not have any directional cutting resistance and cuts well in all directions. It is manufactured in the same sizes as Fome-Cor and is also available in an acid-free version.  This board is now produced with a UV inhibitor to reduce the  possibility  of  ultra­ violet light breaking down  the  foam.  There  are  two  thicknesses-0.125 inch,  or 1/s inch, and 0.210 inch,  which is almost  ¼-inch thick  and is thus often referred  to as ¼-inch nominal. Primex prefers to use thousandths of an inch rather than fractions in referring to thickness. The surface pH is between 6.5 and 7.0 for the regular surface and 7.5 for the acid-free surface. Prime-Foam-X is a little more expensive than Fome-Cor.

 

FOAM, OR FOAM-CENTER, BOARDS 125

 

 

GATORFOAM® BOARD

Gatorfoam has a foam center of Dow styrofoam polystyrene with  a  Luxcell veneer. The veneer is a multilayered, resin-impregnated, Kraft paper surface. Styrofoam is a much harder form of polystyrene foam and  is  much  more dur­ able, but does not have any better aging properties. The hardness of the core combined with the Luxcell veneer results in a board that can only be cut  with a table saw, which significantly reduces its ease for use in picture framing and storage. The major advantage  of  Gatorfoam  is its thickness,  which  ranges from 3!t 6 to l½ inches. The 3!t 6, ½,  and  ¾-inch  thicknesses  are made  in 30"x40" and 40" x 60". One inch and I½ inches are available in 48" x 96" as well.

Gatorfoam is manufactured with two surfaces, one white, the other brown.

The brown Kraft is better for receiving  paint and for  mounting.  There  are also two grades: Gatorfoam I is the standard, Gatorfoam II is a less expensive version with an expanded polystyrene foam center. This board  is  primarily  used  in  model building and as a lightweight substitute for plywood.

 

GILMAN BOARD

Gilman board is like Gatorfoam II in that it has an expanded polystyrene core, which is also known as block foam. The outer sheeting, however, is  a  clay­ coated, white sulfate paper. This paper allows the board to be hand cut by first scoring with a mat knife and then bending, which makes it more practical for picture framing. Gilman board is produced in thicknesses like Gatorfoam-from 3/   1 6     to   1  inch,  but  only  in  41    x  8 1      sheets.

 

ARTCORE

Artcore, manufactured by the Amoco Company, is not a paper,  or a  paper sur­ face foam board. It is entirely plastic. It is  polystyrene  foam  covered  with  a white styrene sheet. Since it is all  plastic,  it  is  also  waterproof.  The  surface sheet is treated with a UV inhibitor to reduce deterioration from sunlight and fluorescent light. The nonabsorbency of the styrene facing can, however, make mounting difficult. I have had areas of several photographs separate from the surface after vacuum mounting. In fact, after experimenting  with  this  board  I have found it has no advantages for framing and storage over the paper-faced

foam board. It would seem more practical for making  displays,  models,  and  signs. Its surface pH is 6.0 to 6.5, and it is manufactured in thicknesses  of 1lt 6,  1/s, and 3 /i 6 inch. The available sizes are comparable to other foam boards.

The contents of this site were previously published in "ART HARDWARE" by Steven Saitzyk 1987, © COPYRIGHT 

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