GLOSSARY

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D

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.

deacidification

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 deacidification 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, desorb

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 sensitised 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-disaster 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.