By Andrew T. Lenz, Jr.

These definitions are to help you understand some basic concepts with regard to conservation.

The American Institute for Conservation revised one of their brochures "Caring for Works of Art on Paper" in 2000 to include a few modifications recommended by Andrew.

Acid-free
Technically, material having a pH of 7 or higher are considered to be acid-free. Acids are evil as far as framers are concerned. Cardboard, for instance has a very high acid content, making it unsuitable for conservation framing, or any framing really. Acids cause papers to become stained and brittle over time.
Some regular matboards claim to have acid-free core and backing paper. Making it completely free of acid, right? Well, no. While this is better than nothing, the boards still contain lignin which down the road results in a more acidic board. These regular boards are buffered with calcium carbonate to neutralize the existing acids, but this buffer will be overwhelmed as time goes on. Also keep in mind that the surface paper is not acid-free and outgasses pollutants, and dyes are used for coloring the surface which fade quickly compared to pigments.
Conservation-grade boards are completely acid-free in the commonly thought of sense of the word.

Alpha Cellulose
This is plant (usually wood) pulp that has been purified, removing lignin and other potentially damaging substances, leaving an almost pure cellulose which is of a neutral pH.

Alphamat
Alphamat is a brand name for a conservation matboard made by Nielsen & Bainbridge. It is composed of alpha cellulose, the surface paper is colored using light-fast pigments, and the board is part of the Artcare family of products utilizing MicroChamber Technology.

Alum
This is a chemical that is sometimes used to set dyes and sizings (adhesives) in papermaking. Alum is not an archival substance and is acidic. None of the conservation matboards or conservation materials include alum.

Archival
As a matter of convention, the term archival with regard to framing is generally considered synonymous with conservation or preservation framing. If something is done employing archival methods, it's done in such a way that the art piece is preserved in the best possible manner, or at least in a manner appropriate for an archive—a storage facility for items meant to be preserved. One could argue that there is no such thing as archival framing as a true archive would not put something on display, but store it away in a safe container away from potentially damaging light.

Artcare
Artcare is a trademark of Artcare (UK) Limited, used under license by Nielsen & Bainbridge, LLC. See MicroChamber Technology.

Buffer
A buffering agent is a substance added to a paper product to either help neutralize existing acids or to help maintain an alkaline pH over time. After a number of years, due to external pollutants, a truly archival board can become acidic even though it contains nothing internally to cause acid formation, buffers help to delay the board reaching an acidic pH level. Two common acid-neutralizing buffers are calcium carbonate and magnesium carbonate. The buffer creates what is also sometimes called an Alkaline Reserve, that is the amount above what is required to create a neutral pH condition in the paper. It's interesting to note that some rare vintage photographs react poorly to alkalinity of the buffers and are best framed using unbuffered pH-neutral boards.

Calcium Carbonate
See Buffer.

Cockling
This just means buckling or waving of an unflat art piece.

Conservation Framing
Conservation framing is preparing an item for display in a manner that preserves the item, keeping it as unaltered as possible while protecting it from degradation. Ideally, anything done to a piece of artwork should be completely reversible, allowing the artwork to return to it's original condition as is it had never been framed.

Conservator
A conservator is an individual who specializes in the care and treatment of artwork, such as restoration or repair of damaged artwork. Conservators go through years of training and apprenticeship.
Framers are not, as a general rule, conservators. It's the old story of "trying to serve two masters." While some framers may be quite knowledgeable in the handling of artwork, before using a framer claiming to be a conservator or who is willing to take on repair of valuable artwork, I recommend first checking with full-time conservators for references on the framer.
Also I, personally, would not let a conservator do my framing. Unfortunately, some of the most poorly cut mats are found in museums having been cut by conservators.
On a side note, by the same reasoning I would not let a photographer frame my photos.

Foxing
Foxing is simply the small medium-brown spots you commonly see on very old paper. These are growths on the paper as a result of moisture and warmth. These can be bleached out by a conservator, though many conservators recommend to let them be. You can help reduce the risk of foxing, which can develop even on new artwork, by hanging your artwork in an environment devoid of high humidity. This can be difficult when your home doesn't get much sunlight. If you get mildew easily in a certain area of your house, avoid hanging valuable pictures there.

Hinges
A hinge is a paper or cloth product used to secure a piece of artwork in place. The easiest to reverse are made of Japanese tissue paper and are adhered with wheat starch paste—these are difficult for inexperienced people to do on most paper artwork due to fact that the introduction moisture can result in cockling artwork where the hinges are located, especially on thinner papers. Hinges should be water-reversible and pH neutral. Ideally, hinges should be weaker than the artwork, the idea being that if the framing package is dropped then hinges will tear first—not the artwork. Masking tape is about the worst tape you can use for hinging, scotch tape, duct tape and packaging tapes aren't far behind.

Lightfast
A paper that resists fading is considered to be lightfast. Papers are colored using dyes or pigments. Dyes are not lightfast, however most pigments are less fugitive than dyes and better maintain their original color. When exposed to light the color red gradually changes to pink. How fast this transition occurs depends on how resistant the dye or pigment is to fading. But just about everything fades, it's just a matter of time and exposure.

Lignin
This is a naturally occurring part of wood pulp that is wonderful for the creation of acids. Hence, this is bad for framing and you'd like any paper products to be lignin-free. Cotton (sometimes called rag board is naturally so, and alpha-cellulose is also lignin-free.

Magnesium Carbonate
See Buffer.

MicroChamber Technology
Zeolites are little molecular traps (microchambers) that capture airborne pollutants and turn them into an inert substance. When manufactured into matboards, gasses that are released by aging wood frames or other acidic materials will not be floating free to harm artwork. The Artcare line of products made by Nielsen & Bainbridge incorporate this technology.

Outgas
As materials age, they release gasses, usually harmful. This process is called outgassing. These outgassed pollutants contribute to an accelerated breaking down of the materials around it. The effects of outgassing can be reduced by utilizing a board incorporating MicroChamber Technology, such as Alphamat.

pH Neutral
The pH scale is used to indicate the acidity or alkalinity a particular item. A pH of 7.0 is in the exact center of the scale and is considered neutral. A lower pH of 6, for instance, is acidic. A higher pH such as 8 is alkaline and is not as damaging to artwork—however, a very high pH can cause problems too. Most conservation matboards are buffered to a pH of about 8.5. This amount above 7.0 is called a reserve.

Preservation
See Conservation.

Rag Board
This is actually an antiquated term still used as a convention. 100% cotton boards at one point were made from old rags. These days museum boards are made from cotton linters, which are the fibers left on the cotton seed after it has been run through a cotton gin. The fibers are actually still too long to use at this point and are actually shortened before the board is made. The cotton fibers are still relatively long compared to other types of fibers and result in a durable, though relatively soft, board.

RagMat
RagMat is a brand name for a conservation matboard made by Crescent. It is composed of cotton, the surface paper is colored using light-fast pigments.

Reserve
Buffers are used to create what is called an Alkaline Reserve, that is the amount above (or in "reserve") what is required to create a neutral pH condition in the paper.

Zeolites
See MicroChamber Technology.


Questions about any other conservation terms? Feel free to contact us.