Absorption: The action by which a liquid or gas is leaked or drawn into the porous or permeable structure of a solid or fluid. This contrasts with adsorption, where the substances are simply held on the surface of the solid material. See also Adsorb, adsorption.

Accretions: Solid pieces of extraneous or foreign matter attached to the surface of artwork or an object such as dirt or food particles. Should the removal of such matter be required, great care must be exercised during the mechanical dismantling process to avoid tears, holes or similar damage. Where the artwork has any sentimental, historical or financial value a qualified Conservator ought to be consulted.

Acid: In chemistry, a compound that produces hydrogen ions (H+) in aqueous solutions. The resulting concentration and state of hydrogen ions in water is known as acidity.

Acidic paper: Depending on the process used in its production, and the materials it is in contact with, paper can be acidic, neutral or alkaline. Many new papers are acidic and although they may initially be quite strong they will rapidly lose strength if they contain strong acids. This is due to chemical reactions that break down the chain length of the cellulose, the main component of paper. When paper loses most of its strength, it is said to be brittle.

Acid-free: A technical term that describes materials, including boards and papers, that have a reading of 7 pH, or very close to 7 pH. Acid-free materials are more permanent and less likely to discolour over time. The term Archival or conservation quality more accurately describes true acid-free conservation quality matboard.

Acid migration: This refers to the contamination, or transfer of acid from an acidic material to one less so or to an acid-fee one. In picture framing this often occurs when acidic papers or boards are placed in contact with non-acidic artwork thereby staining and damaging it.

Acid rain: Rain, or precipitation, with a pH below 5.7. Caused by oxides of nitrogen and sulphur released into the air through the burning of fossil fuels for transport, heat and power. These oxides are converted into nitric and sulphuric acids and washed down in the rain. Acid rain can be particularly damaging to stone buildings, outdoor metal and stone sculpture.

Acrylic: A class of plastics known for their clear optical properties and durability. Acrylics have good resistance to the effects of sunlight and exposure to the elements over a long period of time. They do not yellow significantly or undergo significant changes in their physical properties. Acrylic sheets are used extensively for glazing in picture frames. Perspex and Plexiglas are trade names of manufactured acrylic sheeting. Acrylic resins are also widely used in binders for adhesives, paints and varnishes

Adhesive: A substance capable of bonding or gluing materials to each other by chemical or mechanical action, or both, and which may be activated by water, non-aqueous solvents, pressure, heat, cold or other means. A desirable characteristic of adhesives used in conservation is reversibility.

Adsorption: The action by which a liquid or gas is stopped or held on the surface or outside of a solid material. This contrasts with absorb and absorption, where a liquid or gas is leaked or drawn into the porous or permeable structure of a solid or fluid. See also Absorb, absorption.

Agency, Framing Agency: In picture framing, an Agency is run by an Agent who agrees to have your picture framed but does not actually do it and merely passes the work on to a third party for a fee or commission, much like leaving your clothes to be dry-cleaned at the Newsagent. Agencies were more common in the past, but still exist, particularly in the country. It’s preferable though to leave your artwork to be framed personally by the picture framer, or his~her staff, on their premises. Avoid having your artwork double-handled, loaded into trucks and shipped off to strangers who have not talked to you and may not be professional picture framers.

Alkaline buffer:  Chemicals that neutralize acids present in papers or boards as a result of manufacture or the environment. Various agents may be used as alkaline buffers but magnesium or calcium carbonate are the most common. While this is a useful method to decelerate paper deterioration, it can be damaging when in contact with other materials such as leather or older photographs.

Alpha cellulose: The insoluble part of cellulose composites when in a 17.5% solution of sodium hydroxide at 20¡C under specified conditions. Alpha cellulose is made up mostly of cellulose but may include other materials that are insoluble under test conditions. Because the durability of papers and boards depends to some extent on the absence of non-cellulosic impurities, the determination of true cellulose-alpha cellulose-gives also indicates its stability and permanence. The term alpha cellulose in a paper or board specification generally indicates a high-quality product.

Ambrotype: A 19th century, photographic process that produced a wet collodion negative image onto a glass plate which was coated with black paper or lacquer to give a positive image. A popular photographic portraiture medium during the 1850s.

Aniline Dyes: Today this term refers to any synthetic organic dyes and pigments, regardless of source, as against animal or vegetable colouring materials, natural earth pigments, and synthetic inorganic pigments. Aniline dyes are classified according to their degree of brightness or their light fastness. Basic dyes are known for their extreme brightness, as well as for their lack of colour fastness.

Archival: An inexact term implying materials, products or processes that are durable, chemically stable, of long life and suitable for conservation purposes. The phrase is not quantifiable; no standards exist that describe how long an ‘archival’ material will last. Permanence and permanent are often used to mean the same thing. However, most reputable manufacturers nowadays produce non-acidic, archival-quality materials can be safely used for long-term display or storage of valuable artwork without causing or adding to degradation. These materials usually have additives that slow down deterioration caused by other factors. Archival-quality papers, cards and boards are mostly made from high-quality cellulose fibres such as those from rags. Archival-quality plastics are inert and allied adhesives are stable without acids.

Artwork, or Art: In picture framing, this is the generic term picture framers use to describe something that needs or is going to be framed. When you bring to a picture frame store a photo, print, poster, document, or anything that needs framing or to put into a picture frame, the picture framer will refer to this as the art to be framed, or the artwork that needs framing.

ATG Tapes: Double-sided tapes used to stick mat boards and other materials together. Usually used with an Adhesive Transfer Gun or applicator, available at Art Supply stores.

Auxiliary support:  In picture framing, the structure to which the substratum or support is attached. In a conventional oil painting this is normally a wooden stretcher.

Backboard:  The part of a mat made from a solid piece of mat board, which functions as a protective support for works of art on paper. This term is sometimes confused with a backing board, which serves a different function. See also Mounts, mats.

Backing Board:  A protective sheet of material attached to the back, or verso, of a frame, or sometimes directly to the stretcher, to isolate the back of the support from the environment. Backing board materials may be of Regular, Conservation and Museum qualities. Regular backs include MDF, cardboards, plywoods, chipboards and masonite made out of unbleached wood pulp containing harmful lignin, that progressively yellow, become more acidic with time and may damage your artwork. Conservation backs, such as foamboards, are available with an acid-free rating and will not damage your artwork. Museum backs have all the qualities of Conservation foamboard, are of higher-quality, and the polystirene core is sandwiched with cotton rag paper sheets. The quality of a backing to be used in a particular picture framing job is decided in consultation with the Customer since not all prints are created equal. An inexpensive, commercial print or poster would not warrant the extra expense of Museum or Conservation materials whereas a fine art limited edition, etching or watercolour most probably would.

Baryta coating:  A coating made from the mineral, barium sulphate. It is opaque and white. In photographs, the baryta layer is made of barium oxide with a binder to hold it together, or barium sulhpate suspended in gelatine. It is applied to photographic printing papers under the emulsion layer to mask the colour and texture of the paper and ensure a smooth image.

Bevelled edge:  The angled, 45-degree cuts forming the hole, opening or window of a matboard. This allows about 3 mm of the core to be seen. A reverse bevel means the core will not be seen from the front of the mat.

Bleaching:  The cosmetic whitening or reduction of coloured substances by the chemical action of an oxidising or reducing agent. The process is likely to weaken paper or textiles and is rarely a recommended conservation treatment.

Blistering:  Bubbling between layers of paint or between paint and the surface it is covering, often caused by heat.

Bloom:  a) On metals, a loose, flower-like corrosion product which forms when certain metals are exposed to a moist environment. b) On paintings, a cloudy appearance on the varnish of the painting, probably caused by the presence of moisture on the surface of the paint or in the varnish itself at the time of original varnishing. c) On other organic objects, a term used to describe the visible appearance of active mould spores.

Bone folder:  A flat piece of bone or plastic with rounded corners and edges. It is used to score and fold paper and light card when making storage folders.

Brittle/brittleness:  A property or condition of a material, such as paper, board and adhesives, that causes it to break when it is deformed by bending. Paper is said to be brittle when a corner will not withstand two complete folds.

Bronze disease:  A non-protective corrosion of copper and bronze objects, caused by the production of copper chlorides which break down the normally protective surface patinas. Light blue-green blisters form on the surface. When they are touched, they crumble and fall away leaving a pitted surface. The corrosion is cyclic, setting up reactive and destructive corrosion cells on the surface of the metal.

Buckling:  When a flat, or regular surface goes out of shape. Distortion caused by water damage, heat, expansions, shrinkage or compression.

Buffered: (See Alkaline Buffering)

Calibrate:  To check, and correct if necessary, the accuracy of an instrument against a standard.

Camera obscura:  An early form of camera consisting of a darkened box with a hole-or lens-in one side which casts an image of an object onto a ground glass screen or sheet of paper. The image was then traced rather than recorded photographically.

Carbonaceous:  A substance which contains carbon.

Carcinoged:  A substance which produces a cancer in a body.

Carte-de-visite:  A photograph, originally albumen, attached to a cardboard backing and used as a visitor’s card. The photographs were nearly always portraits and were collected enthusiastically and mounted in albums. The mass-produced photographs were taken by a camera which could take more than one image on a single glass plate negative. They were popular from 1860 to the late 1890s.

Cataloguing:  Creating a record according to specific and uniform principles of construction. Museum cataloguing usually includes details of any numbers assigned to the object; the object name; details of manufacture; history and use; storage location; physical condition; and often some form of classification.

Cellair:  A thin polyethylene foam padding, used for packaging, wrapping, and the lining of rebates and frames. A similar product is called Protecta Foam-this is a trademark/brand name.

Cellulose, cellulose fibres:  A complex carbohydrate forming the walls of the cells in all plants. The chief source of cellulose is wood, cotton and other fibrous materials, for example, flax and hemp. Cellulose is the raw material for the manufacture of paper, rayon, cellulose lacquers and films.

Cellulose nitrate:  Cellulose nitrates are a range of compounds formed by treating cellulose with a mixture of nitric and sulphuric acids. They are used in the manufacture of plastics, lacquers and explosives. They were also used extensively as a film base until 1951, but were abandoned for this purpose because of their high flammability. See also Nitrate film.

Chemical deterioration:  Deterioration caused by chemical changes within a substance, or by chemicals from another source acting on the structure of a substance.

Chemical reaction:  The process by which chemicals combine with each other to form products which differ from, or alter, the original substances.

Chloride:  Often found in nature in a chemical compound called salt where chloride is chemically bound to a metal such as sodium. Chloride salts may cause abrasions or produce harmful chemical reactions such as those associated with bronze disease.

Chlorinated hydrocarbons:  Any of a wide variety of organic compounds, liquids and solids. Cholorinated hydrocarbons are produced when chlorine is chemically combined with hydrocarbons such as methane, ethylene and benzene. Chlorinated hydrocarbons are used as solvents and plasticisers. Polyvinyl chloride-PVC-is a plastic form of chlorinated hydrocarbon. See also PVC.

Cibachrome:  A photographic process for making colour prints from colour slides or transparencies. It produces a high-quality, direct, positive photograph using a silver dye-bleach process. Cibachromes were produced with gloss or pearl finishes; gloss cibachromes have a longer life expectancy. The name was changed to Ilfochrome in 1992.

Clamshell box:  Well-made storage boxes for individual books, similar to Solander boxes. They are handmade and are relatively expensive. See also Solander box.

Classification:  Assigning objects into groups within a system of categories. Classifying or grouping similar objects helps in retrieval when the objects are required.

Clear title:  Ownership without restrictions or conditions. It is important to establish clear title when accepting donations or bequests to collections.

Cleavage:  The separation of the layers of paint from the ground of a painting, which may cause cracking and blistering between layers. This eventually causes the paint to flake off.

Coated paper:  A slick, glossy paper, usually very opaque white, created by coating the surface with adhesives, clay, calcium carbonate or other mineral pigments to provide a smoother base for printing. Also called glossy paper. Coated papers often stick together when wet.

Cockling:  Wrinkling or puckering caused when paper, fabric, or any sheet of support material dries unevenly.

Collection:  The body of acquired objects held in title by the collecting organisation; or the accumulated items held by a collector.

Collection management:  All activities related to the care of a collection from the time an object is acquired to its eventual disposal. Collection management covers documentation-registration, accessioning, cataloguing; handling-storage, conservation, display; loan and disposal of objects.

Collection survey:  Information collected about the state of a collection or part of a collection, at a given time. Collection surveys can be as broad or as detailed as necessary. They are a snapshot of the collection, and a means of examining and recording the condition of a whole collection, rather than of a particular item.Collection surveys are useful for resource planning, collection maintenance, and developing conservation plans. Also called conservation surveys.

Collodion:  A solution of cellulose nitrate compound in a mixture of alcohol and ether. It was used in photography as the basis for the wet collodion process from the 1850s.

Composite object:  An object made up of different materials; for example, metal and wood; leather, wood and feathers. Care must be taken that storage and display conditions are suitable for all the materials which make up the object.

Condensation:  The process by which a gas or vapour becomes a liquid. In museums, galleries and libraries, a change in relative humidity can cause condensation of water in enclosed cases, causing damage to objects.

Condition report:  A document which details the condition of an object and is used as a tool to determine change in the object over time. Ideally, condition reports should be produced as soon as an object is acquired. They may also be produced as part of a collection survey; prior to conservation treatment; or as documentation to accompany travelling exhibitions or loans.

Conditioning:  A process of gradual adjustment to new and/or different conditions of temperature and relative humidity. This is achieved through small incremental exposures to the new environment over time. The length of time that conditioning takes will depend on the item and the extent of the environmental differences. See also Acclimatise.

Conservation:  All actions aimed at safeguarding cultural material for the future. Its purpose is to study, record, retain and restore the culturally significant qualities of an object with the least possible intervention. See also Preservation; Preventive conservation; Restoration.

Conservation framing:  A broad term for using the various, conservation-approved, picture framing methods and practices which involve the usage of conservations materials to protect, conserve and preserve any and all artwork and prolonging their lives. In picture framing, this includes the materials, processes and technique employed by professional picture framers to conserve or preserve, with as minimal a deterioration as possible, the original condition of the item being framed. This process must also embody the principle of reversibility, ie:, the item to be framed must be capable of being safely deframed, disassembled, removed or detached should the need arise to do so in the future. Also synonymous with museum-framing, this process helps to protect artwork against the effects of sunlight, acids and pollutants that yellow, fade and damage the art. Specially selected conservation materials, archival matting, hinging, frame sealing and UV protective glazing (glass or acrylic) may all be used to increase the stability and longevity of framed items. Conservation and preservation are crucial criteria when framing articles with financial, personal value or are simply irreplaceable. It focuses on using acid-free materials such as the mat boards, backing, and mounting materials. Acids in many, cheaper picture framing materials, including cardboards, plywoods and spray-glue, can cause acid-leaching, staining, discolouration, deterioration, brittleness, slow disintegration, of your valuable artwork. By requesting conservation-rated materials, you can be sure your framed artwork will be well-preserved to stand the test of time. Generally speaking, conservation materials, processes and techniques are not used for a range of ephemeral, replaceable or commercial prints or posters since the added cost of conservation picture framing is not usually regarded by customers as commensurate with the value of the item.

Conservation grade:  An indication of the purity or quality of materials used in conservation. Conservation-grade boards and papers are made from 100% rag-usually cotton fibres-or purified wood pulp which has the acidic lignin and other contaminating components removed. The terms ‘conservation-quality’ and ‘museum-quality’ are used differently in many countries, therefore, specifications should be checked when purchasing. See also Museum-quality.

Conservation mounting:  Conservation approved mounting methods using acid free materials that protect artwork, documents and photographic prints, and help prolong their lives. See also Conservation framing; Mounting.

Conservation plan:  Preparation of a strategy for the long-term care of collections. Developing a conservation plan involves identifying the conservation needs of collections, prioritising them and allocating resources to deal with them.

Conservation-quality:  See also Conservation grade; Museum-quality.

Conservation standards:  Agreed standards of care needed for the long-term conservation of collections.

Conservation survey:  See Collection survey.

Copysafe sleeves:  Ring binder, plastic sleeves made from polypropylene with tiny bubbles on the inside to prevent photocopies from sticking to the sleeve. The word ‘Copysafe’ is always embossed along the ring-binder edge of the sleeve.

Corflute:  A synthetic, corrugated plastic which has been used as a backing board in recent times-this is a trademark/brand name.

Corflute:  A synthetic, corrugated plastic which has been used as a backing board in recent times-this is a trademark/brand name.

Corner rounder:  A device for rounding the corners of paper mount board and polyester sheets. Used to remove the corner points of polyester, which is used in encapsulation, in order to avoid damage to materials during storage.

Corrosion:  Gradual deterioration of a solid-especially a metal or alloy-due to chemical processes such as oxidation or the action of a chemical agent. Some corrosion products, like patinas, can be protective; however others, like rust, can be harmful to metals. See also Galvanic corrosion; Patina; Rust; Tarnish.
Crosslinking:  The formation of side bonds between different polymer strands which leads to a change in the physical properties of the material, such as loss of flexibility and colour change.

Cultural heritage:  A tradition, habit, skill, art form or institution which is passed from one generation to the next. See also Significance.

Cyanotype:  A photographic process that produces an image with a characteristic blue colour, also called blue-print process or Prussian-blue process. It is called cyanotype because the paper is sensitized with an iron/cyanide solution. Cyanotypes were produced from the 1840s, but became popular between 1885 and 1910. They are highly sensitive to alkalis and should not be placed in contact with alkaline-buffered storage papers.

D-rings:  Hanging devices in which metal straps secure a D-shaped ring. This is a very secure method of hanging, as the straps are secured into the frame with screws.

Dacron:  A strong, crease-resistant polyester fibre-this is a trademark/brand name. See also Polyester.

Daguerreotype:  A photographic process in which a positive image formed by mercury vapour is produced on a copper plate coated with a highly-polished layer of silver. The daguerreotype has a mirror-like surface and is usually in its own decorative and protective case. Popular from 1839 to the 1860s.

Deaccession:  The process by which objects in a collection are removed, other documentation is amended and the item is made ready for disposal.

De acidification:  A common term for a chemical treatment that neutralises acid in a material such as paper, and that may deposit an alkaline buffer to counteract future acid attack. While de acidification may increase the chemical stability of paper it does not restore strength or flexibility to brittle paper.

Dehumidifier:  A machine which reduces the humidity in the atmosphere by using refrigerant coils, desiccants or absorbent drying agents.

Deionised water:  A substitute for distilled water in photographic and some conservation processes. Deionised water is a solvent from which ionic impurities-or free radicals-have been removed by passing it through anions and cation exchange columns. Anions such as chloride and sulphate and cations such as sodium, calcium and magnesium are removed.

Denier:  A unit of weight used to indicate the fineness of silk, nylon, etc. The lower the denier, the finer the fabric.

Desorption:  The removal of materials by breaking chemical bonds from the surface of a solid so that they become gaseous. The reverse of adsorption. See also Adsorb, adsorption.

Developing-out paper, DOP:  A sensitized photographic paper which uses a chemical developing stage for producing the image either as a contact print or an enlargement, as opposed to printing-out paper which requires no chemical development. See also Printing-out paper.

Digital:  Digital means by numbers. A digital watch displays the current time as a set of numbers which change abruptly at regular intervals; whereas an analogue watch models the passage of time by hands which move smoothly around its face. See also Analogue.

Disaster kit, disaster bin:  A basic, portable set of supplies needed for coping with minor disasters-more extensive supplies are kept in a disaster store. Disaster kits can be mobile or static, but they should be easily accessible and able to be moved quickly and safely. In addition to basic materials and equipment, they should contain a checklist of procedures or emergency information sheets and a list of emergency contacts.

Disaster preparedness:  Being prepared to implement practices which will speed the reaction and recovery phases after a disaster. More generally, disaster preparedness refers to the entire process of planning and equipping for a disaster. It includes anticipating the sorts of disasters which could occur and having procedures in place to deal with them: usually in the form of a counter-disaste r or disaster control plan. See also Counter-disaster plan; Hazard assessment.

Disaster store:  A room dedicated to holding an extensive range of equipment and supplies for disaster recovery, including stocks to replenish disaster kits or bins.

Disinfest:  To get rid of vermin, especially lice or rats.

Dispersing agent:  A substance that increases the stability of a suspension of powdered particles in a liquid medium by separating the individual, suspended particles.

Documentation:  In museum cataloguing, the process of record-keeping for each object in a collection. Documentation includes records on details of the object, provenance data and any subsequent museum use of the object. Written records of information and decisions about the operation of an organisation and the objects in its collection. In museums, galleries and libraries this can include policies, plans, condition reports and collection surveys.

Dropback box:  Another name for a Clamshell box. See also Solander box.

Dry rot:  A fungal disease which attacks seasoned timbers, often causing the wood to be reduced to a dry, crumbly texture and to collapse.

Dust:  Particulate material which is or has been airborne and which is a specific size. See also Particulate matter.

Dust jacket:  For books, a paper covering folded around the cover for protective and advertising purposes. Also called a book jacket, dust wrapper, or jacket cover. For small, three-dimensional objects, any protective covering made of cloth or paper which will protect the object from dust and dirt.

Dye:  A material employed for giving colour to textiles, paper, leather, wood or other products. Dyes can be natural or artificial. Many chemicals will stain and colour other materials, but a product is not considered a dye unless it imparts a distinct permanent colour to textiles. Dyes dissolve completely in their binding solution-unlike pigments, which remain suspended. See also Aniline dye; Pigments.

Electromagnetic radiation:  Radiation consisting of particles or waves of energy associated with electric and magnetic fields, produced by the acceleration of an electric charge. Electromagnetic radiation is emitted by matter in discrete quantities of energy called photons. The type of electromagnetic radiation-whether it be infrared, radio or visible light-depends upon its frequency. The types of electromagnetic radiation of most concern in conservation are light and ultraviolet radiation. These form part of the electromagnetic spectrum. See also Electromagnetic spectrum; Frequency; Wavelength.

Electromagnetic spectrum:  The range of frequencies over which electromagnetic radiations are propagated. The lowest frequencies are radio waves; increases of frequency produce infrared radiation, light, ultraviolet radiation, X-rays and gamma rays. See also Electromagnetic radiation; Frequency; Light; UV radiation; Visible spectrum.

Electronic media:  Media which depend upon the use of electrical means to store, transmit and reproduce data or information. Electronic information may be accessed through the use of a storage device such as a sound cassette, CD-ROM or floppy disk and an electronic device for reading, processing and displaying the information such as a computer.

Electroplating:  The application of a metallic coating to a surface by electrolytic action; that is, by depositing metal from a solution of one of its salts onto the surface, using an electrical current. The principal function of electroplating is to make a cheaper metal look like silver. It is used widely for domestic cutlery and plate.

Electrostatic:  A material which is electrically charged so that particulate matter is attracted to it and held by the charge.

Emulsion:  In photography, the word emulsion refers to the layer of binder containing the light-sensitive materials. The most common emulsion has been gelatine, but albumen and collodion were also used. In scientific terms an emulsion is a suspension of one liquid in another. When referring to paints and adhesives, emulsion means a liquid-usually water-containing small particles of synthetic materials and other chemicals. The materials and chemicals undergo chemical changes as the water dries off, and a tough, insoluble, continuous film of paint or adhesive is formed.

Encapsulation:  A form of protective enclosure for paper and other flat objects. It involves placing the item between two sheets of transparent polyester film and sealing some or all of the edges. The object is thus physically supported and protected from the atmosphere and during handling. Because the object is not fixed to the polyester, it can be removed by cutting one or more edges of the polyester. Note: The object may continue to deteriorate in the capsule.

Enclosures:  A general term for various types of protective containers constructed for temporary or permanent storage of fragile materials; also known as wrappers. Encapsulation is a form of protective enclosure, as are Solander and other boxes, dust jackets, envelopes and mounts. See also Clamshell boxes; Dust jacket; Encapsulation; Solander boxes; Mats, mounts.

Environmental control:  The maintenance of safe levels of light exposure, humidity, temperature, air pollution, air movement, and dirt inside a building.

Equilibrium moisture content:  A term applied to wood which indicates the moisture content at which the wood neither loses nor gains moisture from the surrounding atmosphere-it has reached equilibrium with the environment.

Extraction unit:  A piece of equipment designed to extract noxious fumes or gases from an area, often consisting of a fume hood/cupboard and a ventilation unit.

Facsimile:  a) a copy of an original, reproducing its exact form and style. b) electronically generated images-text or graphics-transmitted over telephone lines, commonly referred to as faxes.

Fading:  Most light rays, especially the daylight ones, will fade a picture with the worst being the ultraviolet “UV” rays. Normal, clear picture framing float glass blocks about 60% of the “UV” light but this is not enough to conserve colours or avoid fast fading. To greatly retard fading, since total prevention is impossible, consider asking your framer to glaze your artwork with “UV” filtering glass.While this type of glazing is dearer, it’s been proven to block over 97% of the harmful “UV” rays. Here in Melbourne, Australia, picture framing glass is generally available as clear, non-reflective (glass etched on one side to reduce reflection),”UV” filtering clear, and museum quality.

Ferromagnetic:  The metals iron, cobalt and nickel, and certain alloys are vastly more magnetic than any other known substance; these metals are said to be ferromagnetic. They possess magnetic properties in the absence of a magnetic field.
Filler:  Chalk clay or similar minerals added to paper pulp to extend the pulp, make it less porous, increase the smoothness of the paper and create a better printing surface; also called loadings. Finial:  A decoratively turned or carved vertical ornament which ends a post, corner or edge on a piece of furniture.

Fluorescence:  A form of luminescence in which substances are capable of absorbing light of one wavelength or colour and, in its place, emitting light of another wavelength or colour. This forms the basis for fluorescent lighting. Fluorescent lighting:  Light sources in which electric current is passed through a gas causing electron excitation in the phosphor atoms composing the coating on the inner wall of the luminaire.

Foam Core:  A composite board consisting of outer layers of paper and an inner layer of polystyrene. It comes in various grades, some of which contain acid-free paper-this is a trademark/brand name.

Folding box board:  A multi-ply board specifically manufactured for folding into boxes.

Foredge, fore edge:  The outer front edge of a book; the side opposite the spine. Also spelt fore-edge.

Foxing:  Discolouration of paper, usually in the form of random rust-coloured spots. Believed to be caused by one or more of the following: fungus or mould, impurities in manufacture, high humidity or dampness, and airborne acids. The removal of foxing is generally not recommended as the treatment methods used usually result in weakening of the paper.

Frame, Picture Frame:  The permanent assembly of 3 ( picture frames can be triangular ) or more sections of picture frame moulding. A picture frame or photo frame is usually rectangular, square or round. A picture framer will cut cu-to-size sections from lenghts, or sticks or wood, plastic or metal picture framing mouldings and then join and assemble these into the desired size and shape. It is only after this has been done that the picture frame is  made.

Frass:  The dust-like debris or excrement left behind by wood-eating larvae and boring insects.

Freeze drying (vacuum):  A method of removing water from wet books or other materials. The material is first frozen and then placed in a high vacuum, so that the water, in the form of ice, vaporises in the vacuum without passing through the liquid state.

Freezing:  In conservation work, freezing is used for a number of purposes: Some objects can be frozen to kill insects at all stages of their life cycle. This is a non-chemical disinfestation method. In a disaster, particularly one which involves water damage, freezing can be used to minimise or prevent further deterioration to objects until they can be dealt with adequately. Under these conditions freezing is not a drying technique; and although it will stop mould from growing, it will not kill existing mould spores. It simply stabilises the materials in the condition in which they were found to allow time for priorities, treatment methods and disposal/replacement programs to be established. frequency The number of cycles, oscillations or vibrations of a wave motion or oscillation in a unit of time, usually one second. This term is used in connection with the electromagnetic spectrum, to indicate the amount of energy transmitted by various parts of the spectrum. The more frequent the waves, the more energy they carry and the greater their potential to damage objects. Frequencies in the visible light range are lower than those in the ultraviolet range. See also Electromagnetic radiation; Electromagnetic spectrum.

Friable media:  Those materials used to create works of art which, if the binding agent is not strong enough, can separate from their supports and easily crumble into a powdery form, for example, charcoal and pastels.

Fruiting bodies:  The structures which produce the spores for the reproduction of fungi. In larger species of fungi, the fruiting bodies are known as toadstools and mushrooms. See also Spores.

Fumigation:  The process of exposing objects, often in a vacuum or air-tight chamber, to poisonous gases or vapour: to destroy insects, mildew or other life forms that may endanger them. The chemicals used in fumigation are often highly dangerous to humans.

Fungicide:  A substance which can kill or prevent the growth of fungi. Many fungicides are highly chlorinated substances which remain active for long periods. While stable enough for most normal use, care should be taken that they are used in low concentrations. While the breakdown of fungicides is normally slow, if they are accelerated by contact with some metals they can produce hydrochloric acid. See also Pesticide.

Fungus/fungi/mould:  Fungi are simple microscopic plants which contain no chlorophyll. They are at least 100,000 different species of fungi. Their spores or reproductive bodies are everywhere and await only proper conditions of moisture and temperature to germinate, grow and reproduce. Fungi cause staining and weakening of many types of materials. The best way to control the growth of mould is to maintain relative humidity below 70-80% and to provide good air movement.

Furnish:  A papermaker’s term meaning the mixture of pulp, chemicals, sizing, fillers, dyes and other additives which form the ingredients of a paper.

Glazing: (without spacers) At times, and mostly as a cost-cutting measure, Customers may request that their pictures be glazed directly on the artwork without mats, mounts, spacers or fillets. This is an inadvisable practice that may cause or promote fogging, condensation and even the sticking of the actual image to the glass. Just as temperature fluctuations can cause your car to fog up on the inside, so can the same thing happen inside a picture frame. This fogging, or condensation, can easily damage your artwork by bleeding inks, smudging a gouache or watercolour, soften photographic emulsions ( the image part of a photograph )causing them and other paper-borne art to stick to the glass. It can also promote discolouration or even “fox” (the small brown spots commonly seen on old prints and papers) any paper art. To avoid most if not all of the above, we suggest framing all artwork with either a mat or mount or, if the artwork is large, spacers that are special plastic strips placed under the lip of the frame between the glazing and the artwork.

Hardwood:  Wood obtained from a class of tree known as Angiosperms, such as birch, oak, eucalyptus, maple and poplar. These trees are characterised by broad leaves and are usually deciduous in temperate zones. While most of these trees have strong, hard woods, the term does not refer to a wood’s strength; some hardwoods, like balsa, are actually quite soft.

Hazard Assessment:  Assessment of potential internal and external risks to the collection. See also Disaster preparedness.

Heartwood:  The hard, central wood in the trunk of a tree, containing comparatively little moisture and no sap. See also Sapwood.

Heritage Collections Council (HCC):  Established in 1996 by the Cultural Ministers Council. The HCC is responsible for the publication of this package, the coordination of a National Conservation strategy for preventative conservation, and the development of the Australian Museums On Line (AMOL).

Hinge:  A flexible paper strip-often made from Japanese paper-used to attach an artwork to its mat along one edge, allowing it to be lifted for inspection of its verso. Material, usually gummed cloth tape, which joins the window board to the backboard of a mat along one edge, thereby permitting the window board to be opened. See also Mounts, mats.

Humectant:  A substance which attracts, absorbs or retains moisture, for example, glycerol and sorbitol. Humectants can be used to rehumidify some objects, like leather, to help restore their flexibility.

Humidification:  The gradual introduction of moisture, often through the use of mechanical devices, for example, humidifiers.

Hydrolysis:  A chemical action involving water. In the case of organic compounds, it involves decomposition by interaction with water.

Hygroscope:  A material with the ability to attract and hold water molecules. Extremely hygroscopic materials take up a large percentage of their weight in water in conditions of high humidity.

Illuminance:  The intensity of light falling on a surface. This could also be described as the brightness of the light. Illuminance is measured in lux. See also Lux.

Impasto:  A painting technique characterised by pronounced brush strokes or palette-knife impressions, which stand out in relief, giving a heavily textured appearance. Thick paint, usually oil-based, is used.
Incandescent lighting:  Light sources in which an electric current causes a filament to glow or incandesce, producing light.

Inert:  A material which does not react chemically and will not cause chemical damage to objects.

Infrared radiation:  Electromagnetic waves whose frequencies range from the microwave region to the red end of the visible spectrum. Infrared radiation is measured by the amount of heat given off by an object-in essence, the hotter an object, the more infrared radiation is emitted.

Inherent vice:  Harmful factors that originate from within an object and, without external help, lead to its deterioration. Usually this deterioration occurs through chemical changes in the materials which make up the object. The acidity found in wood pulp paper is an inherent vice.

Inhibitor:  A substance that retards some specific chemical reaction, for example, a corrosion inhibitor. See also Vapour phase inhibitor.

Insect trap:  A general name for a variety of devices used to catch and hold crawling insects. Traps can use bait, pheromone attractions or sticky substances. They are useful for finding entry points and pathways of insects. With regular inspection, information can be gained about the type, number, entry, and direction of insects. From this data an insect control plan can be developed. See also Pheromone attractants.

Internally plasticised:  A process by which a plasticising agent is introduced to an adhesive during the manufacturing process. The adhesive is copolymerised with the plasticiser to form the internally plasticised adhesive. This is in contrast to an externally plasticised adhesive where the plasticiser is not bound to the adhesive.

Interstices:  Small or narrow spaces between things or parts; small chinks, crevices or openings.

Iron gall inks:  Inks manufactured from iron salts and gallotannic acid. Gallotannic acid is found in oak and other galls. Iron gall inks were used extensively for manuscripts. Because these inks contain iron and acid, which both attack paper, they can be very damaging. For example, iron gall ink has been known to completely dissolve paper

Japanese paper: Strong paper originally, and still usually, made in Japan from long-fibred stock such as the paper Mulberry. It is known for its flexibility, strength and permanence, and is used for mending, lining and reinforcing paper. Various types of Japanese papers are used for conservation and bookbinding.

Joint: The part on either side of a book’s spine along which the boards hinge when the book is opened. Books can often separate along the joint if handled and stored incorrectly.

Keys: In painting frames, small, wedge-shaped sections of wood which are inserted in the corners of stretchers and enable the dimensions of the stretcher to be increased when they are tapped in. Also called chocs, wedges. See also Stretcher.

Kilolux hour: The unit used to indicate exposure to light over a period of time. It is determined by the number of hours of exposure multiplied by the intensity of the light-measured in lux-divided by 1,000. Different types of objects can withstand different exposures of kilolux hours, with the most sensitive requiring low levels-no greater than 200 kilolux hours in a year. As an example, an historic costume on permanent display in a museum which is open 5 days a week for 5 hours a day all year round (52 weeks), and which receives light to an intensity of 200 lux while the museum is open, would be exposed in a year to higher levels of kilolux hours than the recommended guidelines:

Lamination: A process of reinforcing fragile sheet material, usually using transparent or translucent sheets of plastic or paper. Hot and cold lamination are possible. The materials used may be archival, but the technique is not an approved conservation practice. It should never be used for valuable items because it can be virtually impossible to remove without damaging the item.

Leather: The skin of animals prepared for use by tanning or a similar process. See also Alum tawed leather; Parchment and vellum; Tanning.

Leather dressings: Oil-based mixtures applied to tanned leather to help maintain flexibility and water resistance. Most dressings contain an oil, commonly Neatsfoot oil. Leather dressings can not prevent chemical decay, protect against acidic pollutants, or restore leather which has become decayed because of chemical influences. They should be used sparingly and carefully on museum objects, as their use can leave the leather sticky and darker in colour.

Leaf, leaves: A single sheet of paper, parchment or vellum, each side of which forms a page of a book. The plural form is leaves.

Light: Electromagnetic radiation with wavelengths capable of causing the sensation of vision. Visible light is within the wavelength range of 400-700nm nanometres(nm), or 4 x 10-7 metres to 7.7 x 10-7 metres. Variations in the wavelength produce different sensations in the eye, corresponding to different colours. See also Visible spectrum.

Lignin: A complex organic material that, together with cellulose, forms the woody cell walls of plants. Lignin surrounds the cellulose fibres and provides the stiffness and strength which enables trees to stand upright. It is chemically stable in wood, but becomes unstable when the wood is broken down to make paper. Lignin is susceptible to photochemical deterioration and, as it breaks down, produces acids which are extremely harmful to paper. Therefore, the preparation of pure cellulose by removing the lignin is an important step in the manufacture of pulp for the paper and rayon industries.

Low oxygen fumigation: A method of disinfestation by exposing materials to an atmosphere deficient in oxygen. See also Oxygen scavenger.

Lumen: The measurement unit for the quantity-as opposed to the intensity-of light given out by a light source. The lumen measurement remains constant for a light source and does not alter if the readings are taken at a greater distance from the light source. Measurements of light intensity, which vary according to distance from the light source, are known as lux. See also Lux; Microwatts/lumen.

Lux: The measurement unit used to record the intensity to which a surface is lit, or the brightness of the light. Lux varies according to the distance from the light source. Lux can be measured by a lux meter and is calculated in terms of one lumen per square metre. See also Illuminance; Kilolux hour; Lumen.

Magic lantern slide: A 19th century transparent slide, viewed using a still-picture projector. A magic lantern slide was made up of a positive image on glass and a cover glass bound together using black tape at the edges. The first magic lantern slides were hand-painted images. Photographic magic lantern slides date from 1849; they used albumen emulsion on glass transparencies.

Management by objectives: A management technique for achieving greater efficiency in an organisation by setting targets and motivating staff. Factors impeding the achievement of objectives are identified and action taken to overcome them. Results are appraised periodically and new targets set where necessary.

Manual index: An alphabetical listing, usually on cards, of objects in a collection, classified usually under subject groupings.

Marbled paper: Paper decorated by transferring to its surface intermingled colours which have been floated on a gum solution. Many of the traditional patterns resemble marble.

Matboard: The American name for the coloured cardboard one often sees immediately under the glass of a framed picture and surrounding the image. Also called a mount board in England and passepartout in Europe. Matboard’s mostly fall into three categories: Regular, Conservation and Museum. Regular boards are made out of unbleached wood pulp containing harmful lignin, have a core that will progressively yellow, are not fade-proof, become more acidic with time and may damage your artwork. Conservation boards are made out of bleached wood pulp with lignin removed, have a bright white core, are totally acid-free, with fade-resistant colours using pigments instead of fugitive dyes, and will not damage your artwork. Museum boards have the all the qualities of Conservation Boards and, additionally, are made out of higher-quality cotton rag instead of wood pulp. The quality of board to be used in a particular picture framing job is decided in consultation with the Customer since not all prints are created equal. An inexpensive, commercial print or poster would not warrant the extra expense of Museum or Conservation materials whereas a fine art limited edition, etching or watercolour most probably would.

Microclimate: The climate of a very small or confined area. Microclimates can occur within contained objects such as showcases or book cabinets.

Microcrystalline wax: A petroleum wax containing small, indistinct crystals, and having a higher molecular weight, melting point and viscosity than paraffin wax. It is used in conservation work as a reversible surface coating for objects. Renaissance Wax is a type of microcrystalline wax-this is a trademark/brand name.

Mmicrowatts/lumen, µWatts/lumen: The unit which measures the amount of ultraviolet energy coming from a light source. The unit microwatts/lumen is usually written as µWatts/lumen.

Mildew: Mildew is caused by a number of fungi species and causes brownish spots (foxing)to occur on mostly paper-borne artwork. On watercolours, the fungi digests the sizing almost invisibly and this results in dark spots appearing after the painting is complete. The fungi’s activities can result in serious and unsightly damage to the fibres on papers, canvases, as well as discolouring mat boards and a host of allied problems. These undesirable fungi prefer dark, dank or damp areas, where there is a water leakage, moisture source, high humidity and the damage is usually, but not always, irreversible. An Art Restorer or Conservator, usually found in your local Yellow Pages directory should be consulted for assessment, treatment and possible restoration. Ideally, all artwork, paper and matting boards should be stored in an area with 50% relative humidity at 70 degrees Fahrenheit.

Millboard: A dense, hard-milled, machine-made book board made of pulped waste paper. In bookbinding, it is usually encased in a fabric or leather to make the cover of a book. The better grades of millboard used to be handmade from rope fibre. Called binder’s board in the United States.

Mineral tanned: Tanned using mineral salts to chemically stabilise the skins. Chrome salts are used to produce leathers which are hard-wearing, stable and water-resistant. These leathers are not easily embossed and are generally not preferred for fine bookbinding work. See also Vegetable tanned; Tanning.

Mordant: a) In textiles, a substance used to fix the colour in dyeing or fabric-printing, especially for fabrics of plant origin. The fabric is impregnated with the mordant, then during the dying process the dye reacts with the mordant, forming a chemical bond and attaching it firmly to the fabric. b) In paper making, papermaker’s alum is used as a mordant for fixing rosin size to paper. Because rosin does not attach readily to paper, papermaker’s alum is needed to create a firm bond between the two. c) In gilding and bookbinding, the adhesive used by gilders to secure pigment or leaf metal to paper, parchment or wood; gold size is a mordant.

Mounting: The process of attaching a work to a supporting surface known as a mount or mat, either before framing or as a protective enclosure without framing. See also Backing board; Conservation mounting; Mounts, mats; Window mount.

Mounts, mats: A mount or mat is made from two pieces of mount or mat board which are taped together along their longest edge so that they can open like a book. The flat paper item or photographic print which is being mounted is hinged onto the back board of the mount, which is being mounted is hinged onto the back board of the mount, which supports the work. The top board is called a window mount, and has an opening cut into it which frames the artwork. Mounts protect flat paper items from physical damage; and if they are made from acid-free materials they also help to protect them from chemical damage. If the mount or mat board is of poor quality it can cause damage by introducing acids into the flat paper items. See also Window mount.

Museum-quality: The quality of materials recommended for use in museums for conservation or for the long-term storage of valuable artefacts. These materials do not cause any deterioration in the artefacts with which they are in contact. The term is often used interchangeably with conservation-quality. The meanings may also be different in other countries. Therefore specifications should be checked when purchasing paper and board. See also Conservation grade; Rag paper.

Museums Australia: The national association of museums, art museums, other collecting institutions and those who work in them, including volunteers. Membership is open to those who subscribe to the ethics and aims of the association. Museums Australia was formed in 1993 by the amalgamation of the Council of Australian Museum Associations (CAMA) and other art- and museum-related bodies. Museums Australia is administered by a national council and by branches in each State. It publishes a quarterly journal, holds a national annual conference and, at state level, administers extensive programs for local museums and offers advice to its members.

Mylar, Mylar D: A plastic sheet made of polyester, used extensively in conservation work. Mylar is a brand name; Melinex is another brand name for the same material. Mylar D is one type of Mylar which is inert and safe to use as an archival material-this is a trademark/brand name.

Nanometres (nm): A very small measurement, one/1,000,000,000th of a metre, used when referring to the wavelength ranges of the electromagnetic spectrum.

Networking: a) Connecting and interacting with other groups of common interests. b) Connecting computer systems to each other to exchange information either in-house, locally or through world-wide networks like the Internet.

Nitrate film: Photographic film with a film base composed mainly of cellulose nitrate. Because cellulose nitrate film is highly unstable, subject to oxidation and denitrification, and extremely flammable, it has been replaced by acetate and polyester-based films. See also Cellulose nitrate.

Non-buffered: Refers to materials which do not have any alkaline substances added to their ingredients in order to neutralise acids. Alkaline buffers are added to papers and boards to chemically neutralise acids. Hence alkaline buffers are generally seen as protective. However, some materials, such as colour photographs, can be adversely affected by the alkaline buffering, and non-buffered papers are recommended for use with these items. See also Acid free; Alkaline buffering.

Offgassing: The process of a material giving off gaseous matter, through its structure, into the environment. Offgassing is often the product of fumigation, or of the curing of paints or varnishes.

Organic materials: Originally this term referred to materials derived from living things, that is, from plants and animals. It refers also to synthetic materials containing carbon combined with hydrogen and often with oxygen, nitrogen and other elements. Chemically, these substances are similar to the substances derived from living things. The molecules of organic substances are often very complex and contain a large number of atoms.

Oxidation, oxidise: A chemical reaction in which a substance is changed to another, forming what is called an oxide. This normally happens when oxygen is combined with the substance, or hydrogen is removed from it. The term is also used generally to include any reaction in which an atom loses electrons.

Oxidising agents: Substances which bring about an oxidation reaction. For example, hydrogen peroxide is a strong oxidising agent. There are many oxidising agents in atmospheric gases and pollutants.

Oxygen scavenger: A substance which absorbs atmospheric oxygen, leaving low-oxygen environments. In conservation work, oxygen scavengers can be used to kill insects and some pests by removing oxygen from storage environments, thus providing an effective alternative to fumigation. Oxygen scavengers are also used as a means of preventing corrosion of some metals. See also Low oxygen fumigation.

Ozone: An unstable gas under normal conditions with a peculiar, pungent smell. Ozone (O3) is produced when an electric discharge is passed through air or oxygen. It is present in the upper atmosphere and screens the earth’s surface from excess ultraviolet radiation.

Paper: A man-made substance, generally matted or felted sheets of predominantly cellulose fibres formed on a fine screen from a water suspension of the fibres. Papers can be hand or machine-made. Traditional Western papers were composed of fibres from cotton or linen rags. Modern papers are mostly made from wood pulp. The treatment given to the wood pulp affects the properties of the paper. Paper produced from an alkaline process are usually more stable than those produced from an acidic one. Acidic paper containing a high concentration of groundwood-for example, newspapers and hence a high lignin content-are very unstable. Many Japanese papers are made by traditional methods from a variety of plant fibres. These are valued for their flexibility, strength and permanence.

Paper-based material: Books, documents, art works, photographs and other objects produced on paper.

Papermakers’ alum: Aluminium sulphate, widely used in the papermaking industry to improve the flow of pulp through papermaking machines, and to fix rosin size to paper. See also Alum rosin sizing.

Papyrus: A writing material made from the pith of a giant sedge found in the region of the Nile and used by the ancient Egyptians, Greeks and Romans. It was made by placing strips of pith-the nearer the centre the higher the quality-in a row and then overlaying them with another row placed at right angles to the first. These were moistened and beaten or pressed: a process which released natural gum and provided adhesion. The earliest recorded specimen was found in a tomb of around 3000 B.C.

Parchment and vellum: Parchment and vellum are untanned animal skins. The skins are stretched and treated with lime, and scraped to remove fats and hair from the skins. They are dried and stretched. Because of the processing with lime, vellum and parchment are not particularly susceptible to acid deterioration. Vellum and parchment are very moisture-sensitive. In high humidity conditions, the skins absorb moisture and can distort and cockle. As they dry in low-humidity conditions they become less flexible and distortions and creases can become set into the skin. Correct storage is important.

Particulate matter: Solid particles suspended in the air. These solid particles may settle on surfaces depending on whether rain and wind is present. If the particles form the nucleus for the condensation of liquids, they are called aerosols. If particles settle on surfaces in still air, they are referred to as dust or grit.

Passivating layers: Protective layers which form on particular metals; caused by oxide films which coat the surface and act as ‘insulating’ barriers to slow the rate of corrosion to acceptable levels. This type of passivation occurs with copper and aluminium.

Paste papers: Papers on which the decorative designs have been made with paste to which colouring matter has been added.

Pasteboard: In popular use, a term often applied to any stiff board or cardboard of medium thickness. It originally meant boards formed by laminating or pasting together a number of sheets of waste paper. In bookbinding, it is usually encased in a fabric or leather to make the cover of a book.

Patina: The effect of the environment or artificial chemical and/or physical systems affecting the surface appearance of a work of art. For metals, this usually takes the form of a film of corrosion on the object, usually as a result of exposure to the elements. Many patinas are prized for their aesthetic value-for example on bronzes-or protective properties-for example on lead, tin or pewter.

Perfect binding: A technique developed in the late 19th century for binding books without stitching or sewing their sections. It consisted of single leaves held together by means of a rubber solution applied to their back edges. This type of binding was a predecessor to the modern adhesive bindings now widely used for paperback books. Other types of adhesive are now used: mostly various kinds of PVA.

Permanence: The stability of a material and its ability to resist chemical deterioration. It is not a quantifiable term.

Permanent display: Continuous display of objects for an extended period. This is often made a condition of bequests, irrespective of the conservation needs of the objects, which might require periodic resting, that is, rotating from display to storage

Perspex: An optically clear, thermoplastic resin, polymethyl methacrylate, used as a substitute for glass in certain applications-such as some picture frames. Perspex is a brand name; a similar product has the brand name Plexiglas.

Pesticide: A general term for any material designed to kill pests. Pesticides include specific substances for killing insects-insecticides; fungi-fungicides; plants-herbicides; rats and mice-rodenticides; and other pests. There are two general categories of pesticides: biological pesticides which use growth regulators and pheromone attractants; and general pesticides which tend to use chemicals. See also Fungicide; Pheromone attractants.

pH: A scale of measurement ranging from 0-14 for identifying the level of acidity of solutions-the hydrogen ion H+ concentration. Pure water has a pH of 7 which is considered neutral, whereas acidic solutions fall below 7 and alkaline solutions have pH values exceeding 7.

Phase box: A four-flap box originally invented to meet the immediate, short-term protection needs of an item within a phased conservation program-hence the name-established by the Library of Congress. This type of box is easy to make and is used widely to protect fragile volumes.

Phased preservation: Collection maintenance activities such as the provision of simple boxes, folders or protective enclosures, rehousing and other preventative preservation procedures, while establishing priorities for future treatment.

Pheromone attractants: Pheromones are chemical substances produced by insects to communicate messages. The pheromones that serve as food or sex signals are used as lures in insect traps.

Photochemical, photochemistry: The effect on chemical reactions and the rate at which they proceed in the presence of electromagnetic radiation. Photochemistry is the branch of physical chemistry which studies the effects of light on chemical reactions.

Photochemical deterioration: Deterioration reactions initiated by visible and ultraviolet light and sometimes infrared. Photochemical deterioration is a major cause of deterioration for paper-based material and textiles.

Photochemical reactions: Chemical reactions initiated, assisted or accelerated by exposure to light. For example, hydrogen and chlorine combine explosively on exposure to sunlight, but only slowly in the dark.

Photographic quality: Of such a quality that processing, materials and techniques will actively protect photographic prints from damage and will ensure the maximum life span for the photographic prints.

Photographic-quality mount board: Mount/mat board manufactured without additives or elements damaging to photographs, that is, boards which are acid- and sulphur-free. See also Mounts, mats.

Photo Frame: See Picture frame.

Physical damage: Damage to objects including that caused by mechanical rather than chemical means and resulting in cracks, chips, splits, tears, dents, punctures, breaks, scratches, scuffs and abrasions, as well as soiling, wear and tear, warping, shrinkage, separation of layers of composite materials, graffiti and insect attack.

Picture Framing: with or without acid-free materials It is an inescapable fact of commercial life that acid-free materials are dearer than standard, run-of-the-mill, acidic ones and that picture framers will charge more to frame to a conservation standard. However, a substantial proportion, if not the majority, of artwork framed by picture framers nowadays consists of inexpensive, commercial reproductions, prints and posters printed with ephemeral inks on acidic paper and thus seldom warranting expensive framing. However, a professional picture framer will always give you the first option of choosing and selecting the quality, stable, non-harmful,acid-free materials used in conservation framing.

Pigment: Dry coloured substance in granular state which is mixed, usually ground, with a liquid binding agent such as drying oil, egg white or gum to form a paint. Pigments usually give body as well as colour to the paint-unlike dyes, which do not add body. The principal characteristic of a pigment which distinguishes it from a dye is that it is insoluble in the medium in which it is used, whereas a dye is completely dissolved in its medium. There are numerous instances in which the same chemical product serves as either a dye or a pigment. See also Dye.

Plastazote, Evazote: Polyethylene foams made of relatively inert materials which will not deteriorate or give off harmful gases, used for padding storage boxes and rolls-this is a trademark/brand name.

Plastic memory: The tendency of a material which has been stretched or warped to return to that shape, even after corrective measures have been taken.

Plasticiser: A chemical added to another material to give it increased flexibility. In some plastics such as PVC, plasticisers leach out in time leaving the material brittle. Adhesives for use in preservation should be internally plasticised.

Plexiglas: See Perspex.

Plinth: A low, raised base usually square and rising only a few inches from the ground, which surrounds a display stand. Plinths are used to form a protective barrier so that visitors cannot get too close to an object on display.

Pollutants: Gases and airborne particulate matter usually resulting from combustion or venting of chemicals associated with human, industrial or other activities. Pollutants are one of the major causes of deterioration of museum objects.

Polyester: The term polyester refers to a class of plastics, only some of which are suitable for use in conservation. In a conservation context it usually refers to a clear, plastic sheet made from polyethylene terephthalate. It is noted for its crease resistance, strength, durability and resistance to moisture and chemicals. Mylar and Dacron are polyester products used widely in conservation work. See also Myalr, Mylar D; Dacron.

Polyethylene: A chemically inert, stable, highly flexible, transparent or translucent thermoplastic material. It is fungi-resistant and used in preservation as a protective liner, enclosure, or stable plastic bag. Tyvek is a polyethylene product.

Polymer: A large organic compound made up of a series of smaller repeating units-monomers-joined together by chemical bonds in a regular pattern. The molecular size of the polymer helps to determine the mechanical properties of the plastic material and ranges from a few hundred of the basic units to hundreds of thousands.

Polypropylene” A plastic polymer of propylene, similar to polythene but stronger; as a plastic sheet it is softer than polyesters such as Mylar. In a conservation context, it is used commonly to make sleeves for slides, linings for photographic storage boxes, protective transparent covers for book dust jackets, and Copysafe storage sleeves. See also Polyester; Mylar, Mylar D.

Preservation: All actions taken to slow deterioration of, or prevent damage to, cultural material. Preservation involves controlling the environment and conditions of use, and may include treatment in order to, as nearly as possible, maintain an object in an unchanging state. In the case of archival material, moving image and sound, this may include transfer to another medium. See also Conservation; Restoration. Preservation is a broader term than conservation: conservation activities form part of a total preservation program. Preservation includes activities carried out to repair or treat damaged materials and activities taken to prevent or delay material becoming damaged-preventative preservation.

Pressure sensitive tape: Sometimes called ‘sticky tape’. Adhesive tape that adheres to a surface when pressure is applied. The adhesive frequently degrades leaving a brown residue, which stains and makes the paper brittle. Some conservation grade pressure sensitive tapes are available but they are not recommended for use on original materials.

Preventive conservation: All actions undertaken to prevent the deterioration of cultural materials and collections. See also Preservation.

Printing-out paper: Light-sensitive photographic paper which was printed in direct contact with a negative and exposed to sunlight. There was no chemical development involved in the production of printed-out images. See also Developing-out paper.

Provenance The proven or documented place of origin, use, history and ownership of an object.

Psychrometer/sling psychrometer: An instrument used to measure temperature and relative humidity. Sling psychrometers are relatively inexpensive compared to thermohydrographs. They provide accurate instant readings but do not permit the recording of temperature and relative humidity over time.

Pulp: The mechanically and/or chemically prepared fibrous mixture used in the manufacture of paper and board. Mechanical pulping separates the wood fibres, while chemical pulping purifies them by removing lignin and other undesirable agents.

PVA, polyvinyl acetate: A thermoplastic with good ageing characteristics, sometimes used as a fixative or sealing agent. PVA is a polymer emulsion and forms a generally insoluble film much like emulsion paints. When applied to a surface, PVA is liquid, but as it dries it forms a continuous solid film. The use of this substance in book repairs is limited because it is not readily reversible. See also Acid-free PVA.

PVC, polyvinyl chloride: A polymer of vinyl chloride. This plastic is not chemically stable and produces hydrochloric acid as it deteriorates. It should not be used for conservation purposes. Plasticisers are used to make PVC more flexible. These leach out over time and cause significant damage. See also Chlorinated hydrocarbons.

Null:

Radiant energy: Energy transmitted in wave motion, that is, the electromagnetic spectrum including visible light, ultraviolet, infrared, heat and others.

Rag paper: European paper was originally made from rags. The earlier papermaking fibres came from linen and hemp rags; and later cotton was introduced. Rag papers are generally much more durable than those made from wood pulp. Rag paper implies quality paper. Modern rag papers are made most often from cotton linters: the short cotton fibres which remain after the longer fibres have been removed for the textile industry. Cotton is a good-quality fibre, but cotton linters is not the top quality.

Raking light: Light from a light source which is placed at an angle to the object during its examination, in order to emphasise the surface characteristics of the object. This strongly angled light will throw up shadows where uneven surfaces appear, making it easier to see creases, lifting paint layers or other damage to a smooth surface.

Reaction: In a disaster, the action taken on notification of a threat, including initial response procedures and prior to the recovery stage. Reaction to disasters should be based on sound planning. For the use of this term in its chemical sense, see Chemical reaction. See also Counter-disaster plan; Initial response procedures; Recovery.

Rebate: The L-shaped groove on the inside edge of a picture-frame into which the picture, glazing, mount and backing board fit. Also spelt ‘rabbet’.

Reconstruction: The actions taken to recreate, in whole or in part, objects or other cultural material.

Recovery: In a disaster, the action taken to salvage the collection. Recovery includes the sorting, documenting, drying, cleaning, rehousing, repairing and relabelling of items damaged in a disaster. See also Counter-disaster plan; Initial response procedures.

Red rot: A type of deterioration of leather, which generally takes two forms: 1) a hardening of the leather, causing it to become brittle (commonly found in leathers up to about 1830); and 2) a powdering of the leather, which can be so severe as to destroy it completely. This latter deterioration appears to affect virtually all leathers, and is apparently influenced by several factors, including (possibly) the tanning agent or agents used, ultraviolet light, atmospheric conditions (sulphur dioxide pollution) and how frequently or infrequently the book is handled.

Reducing agents: Substances which remove oxygen from, or add hydrogen to, other substances. For example, photographic developers are reducing agents: they supply electrons to a system.

Reduction, reduced: A chemical reaction in which one substance is changed to another by the removal of oxygen, or the addition of hydrogen to it. The term is also used generally to include any reaction in which an atom gains electrons.

Reemay: A spun-bonded polyester which is resistant to adhesives. Reemay looks like Vilene-which is used in dressmaking-and is used in paper conservation as a release material for paper and paste repair and as a support when washing fragile papers-this is a trademark/brand name.

Register: a) The book, file, computer database or similar system where objects in a collection are recorded. b) The basic record or documentation of objects. c) The process of entering an object into the recording systems of a museum, also called registration.

Registration: The process of entering an object into the recording systems of a museum by assigning a unique number, physically numbering the object, recording that number in a register and noting brief details of the object and its acquisition.

Relative humidity: The amount of water vapour contained in the air at a particular temperature compared with the total amount of water vapour the air can contain at that temperature. Relative humidity-RH-is expressed as a percentage. Various materials respond differently over a range of humidity levels and there is an optimum level of relative humidity suitable for the display and storage of specific materials. The suggested RH for a mixed collection would be in the range of 45-55%.

Release paper: A thin, translucent paper coated with a substance such as a silicon preparation on one or both sides to render the surface slippery and resistant to sticking. It will withstand the application of heat without sticking or otherwise damaging the work.

Replica: A copy, facsimile or reproduction of an item, ideally-particularly in art collections-made by the maker of the original or under their direction.

Restoration: The actions taken to modify the existing material and structure of an object to represent a known earlier state. See also Conservation; Preservation.

Reversibility: Ability to undo a process or treatment with no, or minimal, damage to the object. Reversibility is an important goal of conservation treatments, but it must be balanced against other treatment goals or options. Full and total reversibility is an ideal which in reality is almost impossible to achieve.

Ribloc: A ribbed, lightweight material used for making rollers on which to store unstretched paintings or large textiles-this is a trademark/brand name.

Rollover edge: In picture framing, the edge of the canvas which is ‘rolled over’ the auxiliary support. See also Tacking edge.

Rust: Corrosion products-iron oxides-which form on the surface of degraded iron and iron alloys. Rust is not protective, and will accelerate the corrosion of the metal until there is no iron left. See also Corrosion.

Salted paper: The earliest form of silver halide contact printing paper, dating to the mid-1830s. Artist’s paper was imbued with a solution of common salt and dried. This paper was sensitized under candlelight by floating it on a solution of silver nitrate, then dried in the dark. Sunlight exposure behind a negative produced a strong, visible image which was toned in gold or platinum before fixation.

Salted paper:e:Salvage: The act of saving objects from danger and destruction caused by a disaster. This includes drying, cleaning and repairing damaged items.

Sapwood: In a woody plant, the softer wood between the inner bark and the heartwood.

Screw eye: A metal ring with a screw fixing at one end. On a picture frame, the screw fixing is screwed into the frame and the ring used as the hanging device.

Sealant: A coating applied in paste or liquid form that hardens or cures in place, forming a seal against gas or liquid entry. Sealants are designed to reduce the porosity of objects and/or act as barriers to water, air, atmospheric pollution, insects and/or dirt.

Serate: Jagged edged, or serrated; having a saw-tooth effect.

Significance: The value attached to objects, sites, activities, or ideas by communities at a local, regional or national level. See also Cultural heritage.

Silica gel: A commonly used water-absorbing chemically inert substance composed of silicon and oxygen which can be used to control humidity within closed containers.

Silver mirroring, silvering out: A type of deterioration of silver-based photographic images, in which the metallic silver particles are oxidised to produce silver ions which migrate to the surface of the image and are reduced back to metallic silver. This causes a characteristic mirroring effect. It is a common problem which affects most 19th century gelatine developing-out prints.

Sizing, sizes: The addition of materials to the paper pulp, or impregnating the paper after it is made, to strengthen it and impart other desired characteristics, such as resistance to the penetration or surface-spreading of inks and resistance to abrasion. Rosins, gelatin, starches and synthetic resins are used as sizing agents. Sizes used in permanent paper are alkaline.

Softwood: Wood obtained from a class of trees known as Gymnosperms, or conifers, such as pine and spruce. While trees like pine have soft, easily worked woods, the term does not refer to a wood’s strength-some softwoods are actually quite hard.

Solander boxes: Boxes of very sturdy construction, with a shallow ‘clam-shell’ design and a hinged lid which opens out flat and closes firmly.

Solvent: A liquid which is capable of dissolving solid materials. Solvents are used because in liquid form they dissolve materials like resins, and plastics used as coatings, and because they evaporate quickly. Water is the most common solvent; however, conservation treatments often require the use of stronger chemical solvents. Some of these can be hazardous to health, and should be used and handled carefully.

Spalling: The flaking off, or splitting into chips, of small pieces of the face of a stone, usually caused by frost damage.

Special purpose materials: Objects which do not meet a museum’s acquisition criteria but are intended to be used for prop, educational or swap purposes. See also Study collections.

Spontaneous combustion: The ignition of a substance caused by the rapid oxidation of its own constituents, without heat from any external source. Nitrate films are very susceptible to spontaneous combustion.

Spore: Asexual reproductive cells of fungi. A spore does not have an embryo and so is distinct from a seed. Many different types of spores are produced by fungi.

Stockinet: An elastic, machine-knitted fabric used in making undergarments-this is a trademark/brand name.

Strainer: In picture framing, a wooden auxiliary support made up of a minimum of four members on which a canvas is stretched. It differs from a stretcher in that the corners are not adjustable. See also Stretcher.

Strategic planning: Sometimes called forward or long-range planning, this process integrates the physical, financial, philosophical and educational goals of the organisation. It is based on systematically outlining the organisation’s long-term goals and determining strategies to achieve them.

Strawboard: An inexpensive board which is made mostly from macerated straw. In bookbinding, it is usually encased in a fabric to make the cover of a book.

Stretcher: In picture framing, a wooden auxiliary support made up of a minimum of four members on which a canvas is stretched. It has expandable corners so that its dimensions can be slightly increased when necessary. See also Strainer.

Study collections: Museum objects collected and organised for research or instructional use, not for exhibition. See also Special purpose materials.

Sulphur: A non-metallic element that exists in several forms-the ordinary one being a yellow, rhombic, crystalline solid-and which burns with a blue flame and a suffocating smell. Some sulphur compounds, particularly sulphides and oxides, can cause severe chemical deterioration in objects.

Support: Any material which acts as a base for, and supports the image layer of, an artwork. Paper, metals and glass have been used as supports for photography; canvas and wood panels for paintings; and walls for frescos. See also Auxiliary support.

Surfactant: Compounds which reduce the surface tension of liquids, for example, soap or detergents.

Sizing:  (Alum rosin) This is used in the papermaking process to size boards and papers. Since rosin does not easily attach itself to paper, papermakers use alum-aluminium sulphate to bind paper and rosin. Alum rosin sizing has been in most machine-made papers since the 19th century. It’s a major source of acid in paper and causes to become brittle with age.

Tacking edge: In picture framing, the edge of a canvas which is secured to the auxiliary support. So called because the canvas was traditionally tacked onto the auxiliary support; however, in recent times staples are common.

Tanning: The conversion of raw animal hide into leather by the action of substances containing tannin, tannic acid or other agents.

Tarnish: Discolouration of a metal surface due to the formation of a thin film of oxide, sulphide or some other corrosion product. See also Corrosion.

Text block: The body of a book, including the leaves or sections, before it receives its cover. The text block does not include any of the papers added by the bookbinder, such as the board papers, endpapers and ornamental bindings.

Thermohygrograph: A machine which records temperature and relative humidity. Sometimes called a hygrothermograph. Usually the readings are plotted continuously on a chart recorder. Thermohygrograph must be well maintained and regularly calibrated to be effective. Calibration is frequently made against a standard measuring instrument such as a sling psychrometer. Automatic dataloggers are replacing thermohygrographs and are now the preferred instruments.

Thesaurus: A list of words providing a standard, consistent terminology for use in describing and cataloguing objects. Thesauri can be developed in-house for a particular collection, or developed more generally to meet the needs of people working in specific areas of interest. There are a small number of published thesauri which have been developed for museum cataloguing; these include the international Art and Architecture Thesaurus and the Australian Powerhouse Museum Collection Thesaurus.

Thread counter: A small, fold-out tool available from haberdashers. It consists of a magnifying glass and a measuring square hinged together. One side of the counter is an open square, with imperial measurements on two sides of the square and metric measurements on the other two sides. The square is placed on a fabric and the magnifying glass is folded out to rest above the measuring square. When you look through the magnifying glass, you can count the threads in the fabric against the marked intervals of the measuring square. The tool is also used simply as a small magnifying glass.

Tintype: A photographic process which was a modification of the ambrotype process, with the collodion layer coated on black lacquered iron plates. Also called ferrotype, melainotype. See also Ambrotype.

Total quality management: A customer-focused approach to the management of an organisation, with the broad objectives of meeting the changing needs of customer’s and continuously improving every activity in the organisation.

Transmitted light: Is produced by placing a light source behind an object-as in a light box-so that the light is passed through the object. The light is useful in detecting damage because it shines more strongly through the areas where the object is torn, split or worn. Insect damage, splits and weaknesses in paper, textiles and paintings can often be identified at early stages by using transmitted light.

Tyvek: A polyethylene spun-bonded fabric which is lint-free, water-resistant and inert to most chemicals. It is useful for dust covers and can be used to line boxes, making them acid-free. It can also be used to interleave stacked paintings-this is a trademark/brand name.

UV radiation, ultraviolet radiation: The electromagnetic spectrum is divided into a number of ranges. Within the spectrum, ultraviolet radiation is very close to the visible light spectrum but has a shorter wavelength and higher energy than the visible spectrum. The higher the energy, the more destructive the radiation. See also Electromagnetic spectrum; Visible spectrum.

Vapour phase inhibitor: A form of corrosion inhibitor consisting of stable organic chemicals, often coated onto paper or board, that is placed in containers housing metal objects. The chemicals slowly evaporate, preventing air reaching the articles enclosed in the packaging and so preventing corrosion.

Varnish: For paintings, the removable, outer, protective layer which enhances the appearance of a painting. The varnish may be removed and replaced several times in the life of the painting. For furniture and wooden objects, the transparent surface coating which is applied as a liquid and then changes to a hard solid. All varnishes are solutions of resinous materials in a solvent.

Vegetable tanned: Tanned using compounds called tannins which are derived from plants. Traditionally, leathers used for binding books were vegetable tanned. They are highly susceptible to red rot. See also Tanning; Mineral tanned.

Velcro: A type of tape used as a fastening, comprising two strips of fabric, one with a dense arrangement of small Nylon hooks and the other with a Nylon pile. When the strips are pressed together one hooks into the other sufficiently firmly to hold the fastening together-this is a trademark/brand name.

Visible spectrum: Those frequencies of the electromagnetic spectrum to which the human eye is visually sensitive; radiation that is perceived as light.

Wavelength Light: A form of electromagnetic radiation which travels in waves and delivers energy in bundles or quanta called photons. As the light energy travels, it moves in a wave motion passing through peaks and troughs. The distance between the peaks of the waves is called the wavelength and is measured in nanometres (nm).

Window mount: The upper board of a mount with a window cut into it to frame the artwork. The window mount provides margins for handling the work without directly touching it. It keeps the glass or Perspex in the frame from direct contact with the work. It also plays an aesthetic role in enhancing the visual presentation of the artwork. See also Mounts, mats.

Wood-pulp paper: Paper made from the cellulose fibres from woodchips rather than linen or cotton fibres. This paper is highly acidic and deteriorates rapidly unless treated to remove lignin. Wood pulp with lignin removed is referred to as chemical wood pulp, and is used to make acid-free, permanent papers and boards. See also Acid-free; Lignin; Rag paper.

Wet mounting: The process of gluing pieces of artwork such as large posters and photos to sheets of cardboard, plywood or similar material in order to keep them permanently flat. Unless kept flat, papers tend to get that unsightly, “wavy” appearance often seen in items such as cheaply-framed posters at market stalls in Sunday markets. The waviness occurs because paper fibres tend to expand and contract with temperature and humidity changes. Wet mounting most often involves coating a sheet of cardboard, or plywood, called the “backing board” with PVA glue and then placing and pressing the poster or photo onto it. This quick and cheap mounting method is also permanent and non-reversible, and is only suitable for inexpensive and commercial artwork. It is not recommended for mounting valuable, rare, historical or expensive artwork which is normally conservation-framed.

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