Color UV?

[Zoe Paddy Johnson CIRT CSOS <pjohnso@xxxxxxx>]

In one of my old Biology text books there were two color pictures of some 
flowers.  One was regular color, the other was the same flowers with the 
uv markings showing up as blue.  It is long enough ago that I don't know 
if the blue in the original picture was dropped out.  It wasn't false 
color, because the green was still green.

In some email from Kodak, one of their help desk people said that uv will 
photograph as blue.

Does anyone know how the second picture was made?

My son, Geoff, and I have speculated in the following ways about the 
second picture.

        1. the exposure time was calculated and then divided by 3.  1/3 
        of the exposure was made with a red filter, 1/3 with a green 
        filter and 1/3 with a uv-pass filter (an 18a?).  of course, the
        1/3 exposure time would have to be adjusted by the filter factor.
        color film used.

        2. half the exposure was taken without a filter, and the other 
        half was taken with the 18a. color film used.

        3. an exposure was made with a wratten 12 (minus blue), and then 
        it was double exposed with a wratten 18a?  color film used.

        4. black and white film: an exposure was made with a red filter, 
        another exposure through a green filter, and then an exposure 
        made through the 18A.  These would all be combined in the 
        printing process.

Geoff's guess is #4.  My guess is #2.  Any guesses or knowledgable 
answers will be accepted.  Also, would any of the above methods work to 
photograph parrot feathers.

Thank you.
ZoeJohnson  


------------------------------