Making Sense of Picture Frame Matting Options

Making sense of all the matting options can be a daunting undertaking. With literally hundreds of options available to the picture framer, sorting through all the grades, textures and colors can consume hours of time before finding exactly what one is looking for. With this in mind, this article covers the matting basics with the goal of educating anyone new to the art of picture framing on the subject of mat selection.

The basic steps of completing a typical picture framing project are outline below. While these may vary slightly depending on the artwork being framed, they illustrate that mat selection is typically the very first item selected.

Typical Steps in completing a framing project:

While an entire article could be written on each of the bullets above, in this one, we will focus on the first step, mat selection. When discussing matting, there are two basic things to consider. The first is the grade of the mat and the second is the color of the mat. We will review each of these in detail. Also, in the United States there are two major manufacturers of matting product. These are Nielsen Bainbridge (the same people who make metal frames) and the Crescent Cardboard Company.

Grade refers to the conservation characteristics of the mat. That is, how long will the mat last before it begins to deteriorate and how much acid bleed will occur from the mat to the artwork.

All organic materials will break own and disintegrate at some point in time. The goal of a conservation framer is to delay this process as much as possible by selecting materials that go furthest in conserving the artwork in question. In the world of picture framing, the major anti-conservation culprit is high acidity (a low pH-value on a 1 – 14 scale) and wood which contains cellulose, is quite high in acid. Since matting is made from wood (more specifically wood pulp) in its naturally process form, it is highly acidic. One has only to think another wood-based product, notably newspapers, which yellow and become brittle in the matter of days.

So the key in selecting mat grade is understanding what conservation qualities are required. Of course different artwork requires different levels of conservation. As a case in point, the original copy of the U.S. constitution will require different level of conservation than a university diploma, which again will have different conservation requirements from a poster or digital print. The difference will be in the grade of matting used. These are covered next

Grade #1: Wood Pulp Fibers Core
The most basic mat quality is one that is made from wood-pulp.  Wood-pulp is not a framer's friend because, although entirely natural, it contains alpha-cellulose, which is highly acidic.  Acidity yellows paper-based products and in the case of a picture frame mat, it will leak onto and damage the artwork it is meant to protect. This phenomenon can be readily seen in older frames in which the artwork has yellowed severely around the matting. This grade of mat is available by Bainbridge under the Papermat™, and by Crescent under the Decorative™ trade names. 

Of course the mat board manufacturers are fully aware of this condition, and to mitigate acid migration, the outer layers are chemically treated in order to reduce acidity.  While definitely a beneficial step in the manufacturing process, the problem is that the core of the mat remains acidic and as soon as a mat window is cut, the core is exposed and will leak onto the artwork over time.

For this reason, this very basic grade of matting should only be used for projects that require temporary framing such as trade shows, school projects or perhaps for use in digital photographs which can be readily reprinted if they are damaged after a few years. The framer should expect to see some yellowing within 6 months and significant deterioration within 3-5 years. Bainbridge sells this type of matting under the “Papermat” name, while Crescent calls it a “Decorative” line. Below are some details of each:

Bainbridge Papermat
Available in about 180 distinct colors, this mat has a traditional white core. Some mats in this quality grade are available with black cores which  

Crescent Decorative:
Available in about 120 colors. These are readily identifiable by a part number that begins with the letters CD followed by a number. One may also come across a Crescent mat type called “Berkshire”. This is a matboard sold in bulk to large companies. It has about the same characteristics (if not slightly lower) as the Decorative line.

As a note, frame shops generally do not recommend, and most do not even carry, papermat of such low grade. Rather, this grade can be found in art supply stores. It is really most appropriate for temporary displays lasting a few days, weeks, but no longer than a few months.

Grade #2: Buffered Pulp Wood Cores

In 1991, Cresent launched a line that was designed to strike a good balance between basic mats made with wood-pulp and the very expensive mats made with cotton (covered in the next section of this article). This middle-of-the-road product is made by chemically treating a wood-pulp based mat so that the outer layers as well as the core is chemically treated to significantly reduce acidity characteristics.

The company markets these as "conservation quality" matboard. Although many professional framers might think that statement is a stretch, these mat boards are a good compromise as they offer vastly superior conservation qualities without costing a lot of money.

Bainbridge has also developed such a mat grade. It is sold under the trade name “Artcare”.

Grade #3: Cotton Based Matting

The highest level of commercially available matting is made not from wood, but from cotton. Cotton based materials are available under the ArtcareTM Alphamat® (Bainbridge) and RagMat® (Cresent) trade names. The benefit of cotton is that it is naturally almost entirely acid free and therefore requires very little chemical processing.