Accelerated Aging

Laboratory tests designed to help determine the anticipated life of conservation materials. The tests usually involve the use of high temperatures and humidity to speed up chemical activity.

Acetate Film

A film composed of cellulose acetate that largely replaced nitrate as base for motion picture film.

Acid Damage

The result of high levels of acid in paper caused through faulty manufacturing combined with hydrolysis. The structure of the paper is weakened to the point where breakage occurs quite easily.

Acid Migration

When materials are stored or bound together, the transfer of acid from an acidic item to another of lesser acidity.

Acid-Free Paper

See Permanent-Durable Paper.


When the pH value, as measured by hydrogen ions and hydroxyl ions in an aqueous solution, falls below the value of 7.


Any product capable of bonding materials together. Traditionally, adhesives were composed only of starch, protein, and gums. Modern adhesives are often formed from polymers

Adhesive Binding

Bindings that depend entirely on an adhesive to attach the leaves together. See also Fan Glue and Perfect Binding.

Adhesive Tape

See Pressure Sensitive Tape.


The natural decay of the various library and archives substances. Aging is significantly speeded up by poor environment, such as atmospheric pollution, high temperatures, and high relative humidity.

Air Drying

The use of natural currents, or fan-propelled, air to dry wet or damp paper or areas.


An emulsion made from albumen or the white of an egg.


The buffering of paper with an alkaline solution in order to resist future acid absorption.

Alum/Rosin Size

The practice of combining aluminium sulphate or potassium sulphate with rosin to precipitate a size onto paper to render it less absorbent.


Description of a technology that maintains information in continuous form. A representation of an object that resembles the original. Analog devices monitor conditions, such as movement, temperature and sound, and convert them into analogous electronic or mechanical patterns. Analog implies continuous operation in contrast with digital, which is broken up into numbers. A video recording is an example of an electronic technology that is analog. Digital. Traditionally, digital means the use of numbers and the term comes from digit, or finger. Today, digital is synonymous with computer.

Animal Glue

A protein adhesive made from animal parts (skin, bones, hooves, etc).

Aqueous Treatment

Generally, the treatment of paper (or other artifact medium) with water or solution containing water.


A term suggesting that a material is long-lasting and chemically stable (see Permanent-Durable).


The back edge of a book (codex) along which the leaves or sections are fastened together.


(1) The stamping of titles and designs onto a binding surface by a blocking press. (2) unwanted adhesion between leaves of a book for example.

Blotting Paper

An absorbent unsized paper used to help to dry wet paper through capillary action.

Board Shears

A manual device for cutting large sheets of paper or board.


(1) The outer cover of a book. In Europe, originally made from wooden boards, usually of quarter-cut oak. Book boards are now usually made from recycled compressed paper products. (2) The protective outer covers of palm-leaf manuscripts (lontar) and concertina manuscripts (parabaik).

Book Cloth

A sized and coated textile specially prepared for binding books.


Used to describe a variety of insect larvae that eat and bore through paper and books.


(1) A manufactured container, preferably chemically stable, designed to enclose manuscripts, prints, and photographs. (2) A custom-made enclosure made from board and bookcloth designed usually to secure important books and other artifacts.


Generally used to describe highly deteriorated paper that breaks after a single corner fold.


A strong book-cloth, woven from cotton or linen, now often coated with acrylic.

Case Binding

A binding construction where the complete cover is made away from the book, and into which the book is pasted as a final binding step. Usually, publishers' bindings and those produced by library binders are case bindings.


The chief constituent of plant cell walls. The main component of paper, textiles, thread, etc.

Cellulose Acetate

Generally used in paper conservation as a thermoplastic film to assist the lamination of fragile documents.

Clamshell box

A protective container, often fitted to the dimensions of the enclosed object, hinged along one side to open like a book.

Coated Paper

A highly finished paper designed to produce a brilliant surface for the production of fine colour printing. The paper is coated with clay products which, when wet and partially dried, adhere together in an insoluble wad.


The puckering of paper and other materials because of changes in temperature and relative humidity.

Commercial Binding

Binding by a commercial vendor, sometimes referred to as "library binding". At most libraries, materials bound by the commercial binder include: periodicals, theses/dissertations, and the rebinding of damaged books.


(1) Lengths of flax or hemp to which the sections of the book may be sewn. (2) Fastenings used to secure palm-leaves together.


The removal or neutralization of acids in paper. When paper is thoroughly washed, water soluble acids are often removed to the point of acid neutrality which is further secured and buffered by alkalization through the use of magnesium bicarbonate, calcium hydroxide, or other alkaline products. Deacidification can also be achieved through the use of solvent solutions or vapor-phase methods (see also Mass Deacidification).

Digital Electronic

Digital Electronic is a technology that is used to capture, store, transform, distribute, and present information in quantized electronic form, usually as a sequence of 0's and 1's known as bits (Lynn). Traditionally, digital means the use of numbers and the term comes from digit, or finger. Today, digital is synonymous with computer.

Emulsion layer

The coating layer on which photographic images are contained.


The sandwiching of a fragile piece of paper between two sheets of polyester film, such as Melinex or Mylar. Can be accomplished by the use of an ultra-sonic welder, a radio welder, or by double-sided tape.


Papers or leaves placed at the end and beginning of the book to protect the text and to act as part of the attachment between the book and the cover boards. Most commonly, an endpaper consists of an outer pastedown and at least one fly leaf.

Fan Glue

Used for books comprised of loose single leaves. In this process, the loose text block is clamped at the fore-edge, and the appropriate adhesiveCusually a polyvinyl resinBis applied to the back edges of the fanned out leaves. This ensures that each leaf is actually attached to its fellow.

Fast Back

See Tight back.

Flexible Sewing

A form of sewing where the support material--- thongs, cord, etc.--- stands above the backs of the section folds in a manner which generally requires the cover material to adhere directly to the backbone.

Fly leaf

A leaf or leaves at the beginning and end of a book, being the leaf or leaves not pasted to the boards, or covers, of the book.


A sheet of paper folded once, forming two leaves.

French Joints

Form of binding structure where the boards are set away from the shoulders, usually at a distance of one and a half times the thickness of the board, leaving a narrow groove. Often used for case bindings and for some other binding styles.


The process of using chemicals to kill mold and insects.


See Section.


A substance similar to refined animal glue used for paper sizing, plate-making, and as a protective layer for some forms of photographs.


When used in reference to machine-made paper or rolled woven products, termed Machine Direction.


A term used for a variety of operations. (a) Strips of cloth or paper used to strengthen section folds when a book is resewn. (b) Hinges for bound maps, plates, etc. (c) Folded sections of paper to which sections may be sewn for protection (see also Meeting Guards), and to increase back bone thickness to compensate for insertions.

Halon 1301

A gaseous fire extinguishing system that is now banned from use in most countries because of its role in depleting the Earth's ozone layer.


The top of the page, or top edge of a book.


The term for "high-efficiency particulate air (filter)." HEPA filters in vacuum cleaners and respirators, etc, remove 99.97% of particles more than 0.3 microns in size.

Hollow Back

A binding construction in which the covering material of the spine is not glued directly to the backbone, but attached to it by a hollow tube. When a "made" hollow tube is not used--- as with a common case binding--- the term "loose back" is used.


System of heating, ventilation and air conditioning for environmental comfort.

Japanese Paper

Specifically a strong flexible repair paper hand-made in Japan from fibres derived from kozo, gampi, or mitsumata, forms of the mulberry.

Kettle Stitch

The knotted chain stitch which joins the sections together on a through-the-fold book, usually at the head and tail.


A machine which combines a suction table with a basic paper processor used for filling holes/losses in paper. Especially of value for insect damaged paper.


The outer covering from an animal (usually a mammal) tanned, or otherwise dressed and prepared in such a manner as to render it usable and resistant to putrefaction, even when wet.


The outer covering from an animal (usually a mammal) tanned, or otherwise dressed and prepared in such a manner as to render it usable and resistant to putrefaction, even when wet.


An amorphous polymer that makes up thirty-two percent of wood and acts as a dimensional stabilizer bystiffening the cellulose fibres. However, when wood is ground and pulped to make paper it becomes unstable and causes the paper to darken in the presence of light and may be a factor in acidity. It can be removed from wood-pulp paper through the use of chemicals and bleach.

Loose Back

The form of construction common to most case bindings, where the spine of the case is not glued directly to the backbone, but left loose.

Machine Direction

The direction in which the fibers in a piece of machine-made paper lie. The machine direction should normally run parallel with the section fold. Folding against the machine direction or "grain" results in uneven creasing at the fold line.

Magnetic Tape

A film coated with a layer of magnetic particles.

Marginal Materials Case

A low-cost "phase-box" structure used to secure brittle materials or to provide sound items with temporary protection while awaiting later, more complex, treatment.

mass deacidification

Deacidification on a large scale using solven solutions or vapor phase methods.

Methyl Cellulose

The result of treating cellulose with an alkali followed by methyl chloride. Used as a paper sizing and as a mild adhesive.

Methylene Blue Test

A dye test used to detect the presence of residual thiasulphate film fixative in newly produced microfilm.


Fungi with a filamentous growth form, producing cotton-like or powdery colonies. Mold spores are ever-present in the air, and generally grow on moist surfaces in the absence of circulating air. Because paper is hygroscopic (i.e. capable of absorbing moisture), mold can become embedded. Many molds are dangerous to health.


An open-weave variety of coarse, sized muslin used for reinforcing and, to some extent, stiffening the backbone and joints of the book. Sometimes called super.


Paper made from mechanical wood pulp, as in newspaper or tabloid-type serials. Such paper has poor lasting qualities and darkens quickly when exposed to light because of the high proportion of lignin still present.


Until 1951, cellulose nitrate was used almost exclusively for motion picture film until replaced by cellulose acetate.


As used here, specifically a method of sewing through the shoulder of a sewn book in order to attach new joint materials, and consolidate the first and last few leaves. Sometimes used to describe both oversewing and whipstitching.


Specifically used here to refer to the method of sewing through the edge of the book at an angle in order to "catch-up" previously sewn portions. May be done by hand or machine. Sometimes used to describe both overcasting and whipstitching.

Pamphlet Case

A stiff cover case, either made in the library or purchased from a vendor, in which are attached thin, pamphlet-like materials.


A translucent or opaque material made from the wet, limed, and unhaired skins of sheep, goats, or similar smaller animals, by drying at room temperature under tension, generally on a wooden frame known as a stretching frame.


Paper which is not contaminated with impurities likely to cause its destruction. Generally, current standards consider the following as a mark of permanence: pH between 7.5 and 10, alkaline reserve of 2%, resistance to oxidation (Kappa) under 5, resistance to tearing 350 mN for all papers over 70 g/m. ISO Standard 9706: 1994.


The popular name for polyethylene terephthalate. Very strong and chemically stable. Can be used in transparent sheet or film form (e.g. Mylar, Mellinex).

Polyvinyl acetate (PVA)

A white, water-dilutable emulsion used as an adhesive. It is strong and flexible and preferred for use in bookbinding and the construction of protective enclosures in tropical areas. Because it is largely irreversible, it should not be used for paper repairs.


A folding cloth case with flaps designed to protect thin, loose items, such as pamphlets.

Pressure Sensitive Tape

Filament tape consisting of an adhesive layer and a filament carrier (e.g. Scotch tape, Sellotape). Generally not recommended for permanent paper repair.

Protective Enclosures

A general term for complete enclosures, including: marginal materials cases, boxes, portfolios, etc.

Quarter Buckram

The preferred form of binding for periodicals, especially for those with fan glue binding. The structure consists of acid-free endsheets, binders' board, and buckram spine.


Reback is used for items that have generally sound sewing structures and that need the original bindings restored by rebacking in the appropriate material. It is assumed that some other binding support may be needed (e.g. corners reinforced).


The term rebind is somewhat analogous to recase in that the original sewing structure is retained, but a new binding cover is applied because the original cover cannot be saved. All paper leaf repairs (tears, losses) are performed in situ (i.e. without their removal from the book.


A general binding term applied to an item that will have a new binding (because the original is too deteriorated or is not contemporary with the text), and which has broken sewing. Rare books to be resewn will often be washed, alkalized, resized, and have moderate paper repairs (i.e. fold reinforcement, first and last few leaves supported).


Applied to a book that has sound sewing and paper, but where the case and endsheets 0must be replaced. Treatment usually consists of backbone cleaning, endsheets attachment, rounding/backing, lining, and construction of a new cloth case.

Recessed-Cord Sewing

The sewing through-the-fold of cords embedded into grooves made across the backbone with a fine-toothed saw. The thread passes from one kettle stitch to the other, merely passing on the outside of each cord.


See Rebind


(1) In digital imaging, the number of dots per inch (dpi) with the greater the number the higher the resolution. (2) In microfilming (sometimes called definition), the number of lines per millimeter.


The shaping (by hammering or rolling) of the backbone of a book into a convex shape prior to backing. Rounding distributes the swelling of the section folds and thread bulk, and helps to maintain the book's shape.

Sa paper

"Sa" is the Lao name for mulberry tree (broussonetia papyrifera vent). Its bark is used to make traditional paper, either plain or with an addition of dried flowers.


A single binding unit of leaves, folded together to be fastened with other sections to form the text book. Bibliographers often use the term gathering, and printers use the term signature.


The ridge formed by the backing operation to accommodate the back edge of the cover board.


Generally used to describe the machine stabbing of text books, children's books, etc.


See Section.

Silver Halide

Silver compound used to sensitize microfilm to produce a metallic silver image. Silver halide film is the only type regarded as acceptable for permanence.

Singer Sewing

The use of a modified domestic-type Singer sewing machine for the stitching of pamphlets or sections.


A coating laid onto paper to render the surface stable and to stabilize the spread of ink. Can be applied during manufacture or retrospectively after paper treatment. Size can be gelatine, methyl cellulose, or various synthetic forms.


The free ends of the cordsthongs, or tapes, on which a book has been sewn. The slips are used to help attach the boards to the book.


The portion of the cover which fits over the backbone.


Portions of the cover board which project beyond the edges of the leaves.


A from of sewing or stitching in which the thread or wire passes through the entire body of the book or section, as in a Chinese double-leaf book.

Sticky Traps

Glue-based traps frequently used in pest control to catch and monitor insects and other pests.


A simple binding designed to reinforce paperbacks. It consists of joint reinforcement with fabric, and board laminated under the covers.


A term implying that the thread or wire is passed through the entire back of the book or unit in one "hit." Used, for example, in Chinese double-leaf bindings.


See Mull.


The extra thickness of the book at the back edge caused by the section folds and sewing thread.


The bottom of the page, or the bottom edge.


Strips of closely woven cotton or linen material, usually ranging from six millimeters to twenty millimeters in width, onto which the sections of a book may be sewn.

Tight Back

A construction in which the covering material of the spine adheres directly to the backbone of the book. Sometimes called a "fast back".


Usually refers to the insertion of replacement leaves to replace missing leaves in mutilated books.

Tissue Reback

A method of binding repair to a damaged outer joint applied to books with light structure (smaller volumes with fairly thin boards), with quite sound leather at the surface but broken or split in the outer joint. In most cases, fine bindings produced from the mid-18th century foward are appropriate for this treatment. As with other reback and rebind, the text block should be sound.

Ultraviolet (UV)

UV is a high energy wave length of light. It is damaging to library and archives materials because it causes fading an weakening.


Originally, a translucent or opaque material produced from calfskin that had been soaked, limed and unhaired, and then dried at normal temperature under tension, usually on a wooden device called a stretching frame. Now, "vellum" is often used interchangeably with "parchment".


As used in this glossary, a method of stitching through and along the back edge of groups of leaves in order to form sections, which may later be sewn together on the frame. May be done by hand or by sewing machine. Sometimes incorrectly used to describe overcasting and oversewing.

Wire Sewing

A late nineteenth century method of machine stitching multiple sectioned books by forcing wire from the inside to the outside of each fold. The wire was clenched through a back liner of canvas or webbing.