Re: IR with no direct sunlight

["Keith Zimmerman" <zz_ir@xxxxxxxxxxx>]

David, you suggest changing the development time when shooting on an 
overcast day.  Would you suggest a starting percentage for changing that 
time?  Here in the Central Illinois countryside, we get a lot of overcast 
days when the seasons change and I want to experiment.

Since I do not have nor have a darkroom, I rely on an excellent lab for my 
processing.  They use TMAX at 75 degrees.  The only variable is the time.

Thanks

Keith Zimmerman
zz_ir@xxxxxxxxxxx
http://homepage.dave-world.net/~vkzimm/infrared.html


>From: "David J. Romano" <romano@xxxxxxxx>
>Reply-To: infrared@xxxxx
>To: infrared@xxxxx
>Subject: Re: IR with no direct sunlight
>Date: Tue, 26 Sep 2000 16:16:24 -0400
>
>Robert,
>Infrared film really functions no different than any other film. Just as 
>with
>regular film, photos taken in direct sunlight will have more contrast. With 
>IR
>film this is still true, but with a more exaggerated effect. If you were to
>photograph with IR film on a bright sunny day, but in the shade, you would 
>get
>pretty much the same effect as if it were an overcast day.  Since shorter
>wavelengths scatter more, areas in the shade are relatively blue, with very
>little IR.  This is one of the reasons why, in general, images on IR film 
>are
>contrastier that with regular film, and why stronger filtration creates 
>more
>contrast: because the shadows are deeper. Longer wavelength IR light 
>scatters
>much less than visible light.
>
>Keep in mind the zone system: Expose for the shadows, develop for the
>highlights. If you photograph on a cloudy day with IR film and develop the 
>same
>way as if it were a sunny day, the images will have low contrast. There 
>will
>less "IR effect", even though all of the objects in the scene still have 
>the
>same IR reflectivity. Try changing the development time to get the degree 
>of
>contrast you need for one of your average scenes. Then try the same thing 
>for a
>scene on a cloudy day. One nice thing about cloudy days is that the images 
>tend
>to be easier to print and there is often a really nice separation of values 
>in
>the clouds which can make a drab day look dramatic.
>
>Changing light conditions makes exposure and development more tricky, but 
>more
>fun.  Personally, I prefer to underdevelop a little to prevent the specular
>highlights, the ones in direct sun, from blocking up. Then I print on grade 
>3 or
>3 1/2 paper to get the contrast back. It is extremely rare for me to make a
>straight print from an IR negative. There is always some dodging and 
>burning,
>often using mulitple filter grades in the same print.
>
>Dave
>
>
>
>Stan Patz wrote:
>
> > >I accidently deleted a message where someone told me that there is no
> > > >necessity
> > >to have bright sunlight in order to shoot IR photos. Can anyone tell 
> >me
> > >more
> > >about his/her experiences under those conditions, some links with 
> >photos
> > >would
> > >be great, too.
> >
> >
>
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