GLOSSARY

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I

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.

initial response procedures

A short list of essential steps which must be taken immediately if a collection is under threat in a disaster.

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.

insecticide

See Pesticide.

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.