Re: EIR in winter?

[Helmut Faugel TE <htf@xxxxxxxxxx>]

On Tue, 18 Nov 1997, Robert Ades wrote:

> Helmut, could you explain what the "wood effect" you're referring to is?

I will try it. The 'Wood effect' is the reflection of IR radiation
(to be precise this reflection of light starts at about 680 nm *) at
leafs. AFAIK this effekt is only visable at living vegation, that
is the reason why 'false color' film is used to monitior forrests
and agriculture. On EIR with a yellow filter living vegation is
showed in shades of mangenta because the leafs reflect green and
IR, green is recorded as blue and IR as red. As most of the leaf
trees throw away their leaf in fall, they are not as attractive
for photography as they are in spring. I do not know what happens
to pines which keep their needles, but I think the show a reduced
reflection of IR. BTW: the effect is named after it's discoverer
Mr. Wood who made the first IR-photographs of landscapes (in 1910)
and noticed that plants are rendered very bright.  


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Helmut FAUGEL                       |  I hate getting junk mails ...
Max-Planck-Institut f. Plasmaphysik |  my correct email address is: 
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Germany                             |  
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