Re: Photographing trees in autumn with Konica IR

[George L Smyth <GLSmyth@xxxxxxx>]

Hannu Jarventaus wrote:
> 
> On Wed, 2 Oct 1996, George L Smyth wrote:
> 
> > I have an explanation of why leaves are so white on my Web page
> > (Rethinking Infrared Photography) if you want the full explanation.  To
> > sumarize, chlorophyll is transparent to IR, so what you're seeing is the
> > reflections from the cell walls.  When this situation changes, so will
> > the leaves in your images.
> >
> 
> George - I photographed two rolls of Konica IR 750 through red filter
> (B+W 091) and my results show, that also yellow and red leaves are
> white (or very light grey) in the pictures. So I think that all
> leaves, as long as they are on the trees, are white in the pictures.
> I have several pictures of trees with different coloured leaves, and in
> the print I can not clearly see which tree has green leaves and which
> has yellow or red. Maybe there still are some differences.
> (One difference is that they are different trees: birch, aspen, maple...)

The reflection of infrared on leaves is not a consequence of the leaf's
color, but of the cell walls within the leaf, as mentioned in my
article.  Reflection indicates a healthy leaf.  When the cell walls die,
you will not see a change in reflectivity.

george

-- 
 Handmade Photographic Images     
  http://www2.ari.net/glsmyth

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Topic No. 7