Matting and Mat Boards

The choice of mat board has a definite influence on the look and condition of your artwork both now and in the future. Mat boards can contain harmful substances that cause the board to have an acidic or alkaline PH and these should be avoided.

Acidic mat board will cause the bevel or cut edge of the opening or window in the mat to turn a tan or brown color. This is a good indication that the mat board is acidic. This acidic material will migrate to the art in time and discolor it as well.

Small amounts of acid in mat boards can react to humidity or other pollutants in the air causing a stain to form along the edge of the window of the mat. This is commonly called Mat Burn and is a sign that damage has occurred.

We use the terms acid-free and archival to describe materials that are safe to use with our art but these terms can be misleading. Materials that have a neutral 7.0 PH are considered to be safe for your artwork. Some mat board manufacturers use an alkaline reserve, or buffering agent built in, often 2-3% calcium, and have a PH of about 8.5. The purpose of this buffer is to neutralize any acids that may develop over time.

The term Rag Board usually is thought of as cotton rag but now it is often made of new cotton fibers and is always acid-free. This is usually true but you have to look out for the ingredients in your mat board. If the rag board is made up of Alum rosin sizing, the board will become acidic and you’ll have problems.

Rag boards made from chemical Wood Pulp Containing Lignin, a naturally occurring material in the wood, will turn brown and acidic over time and the manufacturing plant must remove the lignin to meet safe preservation Standards. Mat boards made from wood pulp from which the lignin and other acidic substances have been removed are called conservation or Museum Board and are the best board to use for the long term.

These boards have had the lignin and other acidic materials removed and are made of a Neutral PH wood pulp, or are made of cotton pulp that is PH neutral as well.

Mat design and decoration is the other side of the matting story. Here you can think of mat decoration and design and the use of accent and color but still be mindful of the conservation qualities you want in mat board.

Yes, you have more to choose from then a plain neutral-toned archival mat for your art. You should be matching the art to the Frame Package, not what goes best with your wallpaper. Mat board comes in 32x40 sheets and in 2, 4, 6, or 8 ply in thickness.

You can cut the boards to whatever size you need to fit your frame. The thickness of the board will give you a different grove thickness on the mat bevel as well as the thicker the board the more strength it will have.

Color is another way to better match your art to its mat package. There are color mat boards that are fully archival. You can choose to add a v-groove design to the mat and not change its archival quality. This technique is very popular.

Mat boards also come in many textures like fabrics and marbling as well as print patterns. An older technique is drawing on lines along the mat board as well as coloring them in with inks or watercolors. You can double-mat your art as well as change the colors used to double-mat; you can even use an oval mat if the art works well with that style.

There are many books available that provide help with framing art, or you may want to go to a good frame shop and ask questions.

Please use the Contact Form if you have comments or questions for me.

For additional information on framing, please visit Mounting Art, Glazing, Backer boards and Dust covers, Conservation and Restoration and Framing Design--Form and Function.

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