Re: IR Filter affects

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On 20 Aug 96 at 23:30, Randy King wrote:

> The affect of filters has been discussed, along with the
> affects of flashes on IR.  It seems that a filter could
> increase the IR output of a flash unit.  Basically, 
> energy absorbed by the filter would probably be dissipated
> as IR.  Is this the case?  If so, how significant is it?

I sincerely doubt that this is the case. All ASA and GN data I posted 
earlier indicate a halvation of the the flash output.
I believe the only absorption possible is in the form of heat; 
otherwise it would equal a fluorescence effect; ie a 'transformation' 
into a longer wavelength. Like UV light is reflected/transformed in 
visible, would visible light then be transformed into IR. 

[I believe there is only one (rare?) form of fluorescence that works
the other way around]

BTW: when starting this list, I was pondering about its name....I was 
temped to call it Infrared- & UV-photography, but thought it might 
scare people off. UV is a rather related field of science, both 
subject- and material-wise (both HIE and IE are highly sensitive in 
UV, even more than for IR!).
 
--
Bye,

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The difference 
between men and boys
is the price of their toys

<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]

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Topic No. 17