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Lexikon
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A • B • C • D • E • F • G • H • I • J • K • L • M
N • O • P • Q • R • S • T • U • V • W • X • Y • Z |
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Absorption
If light is absorbed by paper, it is transformed into heat. The absorption depends on the wavelength of the light. As a result of light absorption, most materials appear coloured when they are examined in white light.
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Ageing
Papers age with time, turning from a white to a yellowish colour, the degree to which this happens depending on the type of fibre from which they are made. For special kinds of information to be carried or stored on paper (e.g. legal or original documents, painted or printed art), the paper should retain its properties for centuries. Newsprint, for example, which is normally produced using mechanical fibres, ages rather quickly. Woodfree graphic papers, which are produced using chemical fibres at neutral pH, age much more slowly. Paper ages over time.
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