Art Terms Glossary beginning with T
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- Tempera
- A process of painting in which egg or egg yolk is used as the binding media for colored pigments.
- Textualis
- Standard Gothic bookhand of the thirteenth century and later; used for ordinary books.
- Thermoluminescence dating
- An examination technique which measures the accumulated effects of cosmic radiation received by a ceramic over time which have been retained within the structure since it was fired during manufacture This radiation results from the decay of radioactive materials; some of the energy of this decay becomes trapped within crystalline imperfections or impurities as electron shifts. If heated again, the accumulated energy is released and the thermoluminescent clock starts anew. T measures the light emitted during experimental heating to about 500º C, which enables the date that the ceramic was last heated to be measured. The relative energy of the light emitted can also vary due to compositional differences, environmental factors such as radioactive soil and the life of the object such as exposure to radioactivity through x-rays in a museum context. For this reason we keep careful records of all radiography exposures to ceramics in our care
- Time-lapse photography
- Recording objects at timed intervals (seconds, hours, days) to show how they change. The camera remains in a fixed position while single-frame exposures are made at regular intervals to document the moving object, such as clouds moving across the sky or a flower blooming.
- Toning
- Changing the overall color of a photograph. Toning can be done in the course of or following the development procedure. During the development process, a number of factors can all effect the final tone, such as the original chemical composition of the print or developer, temperature, strength of the developer, length of development, and means of drying the print. After development, toning changes the chemical composition by depositing other materials on the print, including those containing sulfur or stable materials such as copper, gold, iron, mercury, palladium, platinum, selenium, and vanadium. Gold toning, which usually increases contrast, image stability, and permanence, originated during the era of the Daguerreotype. It was commonly used with albumen prints in order to impart a rich purplish-brown color. Selenium is the most commonly used toner in the twentieth century. It slightly increases the tonal range and density of a print, giving it a darker, richer tone. Like gold, selenium coats the silver in the emulsion, producing a more stable print. Selenium toning can also produce a split-tone photograph on certain papers, creating an image with silvery highlights and rich burgundy shadows. Finally, many photographs use toners to create coloristic effects ranging from various browns, greens, and blues as well as purple, red, and yellow.
- Transillumination
- The method of viewing transparent or translucent images such as slides, transparencies, or autochromes. The positive image is visible when lit from behind or projected onto a surface.
- Transparency
- A positive photographic image on a transparent or translucent support, such as glass or film. Transparencies are intended to be viewed by a transmitted light source, such as a projector or a light box.
- Triptych
- A painting with three panels.
- Trois Crayons
- The French term Trois Crayons (three chalks) refers to a technique using black, red, and white chalk together to achieve a wide range of values, black being the darkest tone, red the middle tone, and white the lightest. This technique became especially celebrated in the drawings of Antoine Watteau, but this sheet is an example by Watteau's mentor, Charles de La Fosse.
- Turquoise
- An opaque sky-blue semiprecious gemstone composed of a hydrated basic copper aluminum phosphate mineral. It has not been identified previously as a pigment in ancient Egypt, although it was carved for amulets and jewelry. It produces a powder weak in tone when ground.
