Ultraviolet radiation

Description

The portion of the electromagnetic spectrum with wavelengths ranging from 100-400 nanometers (nm). Ultraviolet (UV) radiation occurs between the violet end of the visible spectrum and the X-ray region. UV is not visible to humans directly, but may initiate visible, fluorescent reactions in some compounds. It is present in sunlight and is also generated by almost all types of electrical light sources. UV radiation is subdivided as follows:

- UV-A, long wave UV, from 315-400 nm is produced by black lightbulbs and sunlight. UV-A is used for fluorescent light examinations;

- UV-B, middle UV, from 280-325 nm, is produced by sunlamps (tanning booths) and sunlight. This is the range of radiation that is most readily absorbed by organic compounds. UV-B radiation can deteriorate organic materials as well as cause sunburns, skin cancer, and cataracts in humans;

- UV-C, short wave UV, from 100-280 nm, is produced by germicidal lamps. These lamps are used for irradiation and can generate Ozone.

The high energy of UV radiation can initiate chemical reactions, such as oxidation, in many organic materials resulting in discoloration, fading, embrittlement and/or cracking. Glass transmits little UV radiation below 315 nm, while Quartz does not transmit most radiation below 200 nm. UV absorbing chemicals can be added to glass and plastic to prevent transmission of any ultraviolet light.

Ultraviolet was discovered by the German physicist Johann Wilhelm Ritter in 1801. Ultraviolet radiation is involved in examination or analysis techniques like ultraviolet fluorescence photography, ultraviolet visible spectroscopy (UV-vis)...

Synonyms and Related Terms

ultraviolet light ; UV light; UV radiation; UV-A; UVA; UV-B; UVB; UV-C; UVC; actinic light; rayonnement ultraviolet, ultraviolet, UV (Fr.); Colour

Risks

Long-term overexposure of ultraviolet radiation is hazardous to eyes and skin and may produced erythema, photokeratitis (snow blindness), and/or skin cancer. Short-term exposure is sometime used for medical treatments of psoriasis, vitiligo and acne.

UV radiation can initiate oxidation reactions in organic materials.

Resources and Citations

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• External source or communication Comment: Bob Angelo - Gigahertz-Optik, Inc

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989

• Theodore J. Reinhart, 'Glossary of Terms', Engineered Plastics, ASM International, 1988

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000