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Fri, 26 Jan 2001 14:03:55 +1100 |
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University of Melbourne |
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"Burke, Laurence M. II" wrote:
>
> First of all, with relation to the UV issue:
>
> So far as I know, Alistair is correct about incandescents not having
> an appreciable UV component. However I do cringe at his statement
> that the Infra-red aspect is "harmless". It's all relative. If
> your incandescent source is too close to your object, or especially if
> it is in an enclosed space with your object (like a case), then the
> IR becomes very important as it will heat up your object which will
> hasten deterioration.
Sorry, I meant 'harmless' only in terms of the relatively high-energy
activations caused by UV, but not IR, which doesn't carry enough energy
per photon to do very much in 'most' cases.
It is of course true that light bulbs produce a lot of heat, most of it
being radiative IR, particularly in the case of high-temperature halogen
bulbs. One way to deal with this is to use 'hot mirrors' which reflect
IR but transmit visible light. There are also 'cold mirrors' which
reflect visible, transmitting IR. Their main use, I think, is in stage
lighting, so a theatrical supply company could supply them.
They're also listed in the catalogues of Edmund Scientific, along with
many other optical materials that could be turned to good use in display
contexts.
Vide http://www.edmundscientific.com
----------------------------------------------------τΏτ-
Alistair Kwan -
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