GLOSSARY

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T

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.