Re: (Fwd) Re: Color UV?

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

On Sun, 26 Jan 1997, Robert Long wrote:

> On Sat, 25 Jan 1997 21:42:38 GMT, Willem-Jan Markerink wrote:
> 
> |On Fri, 24 Jan 1997 21:01:21 GMT  Zoe Paddy Johnson CIRT CSOS wrote:
> |>> In one of my old Biology text books there were two color pictures of =
> some=20
> |>> flowers.  One was regular color, the other was the same flowers with =
> the=20
> |
> |There's an option that I didn't see in your list.  Think about "black =
> lights",
> 
> Only Zoe and Geoff can give a definitive answer, of course, but my
> reading of their post suggested that it was the film "seeing" UV and
> "reporting" it as blue that was involved--not fluroescence, which
> wouldn't necessarily produce visible blue light.

It was definitely not fluoresence.

> But another possibility that I don't remember from their list was that
> the "plain" photograph was made through the usual UV-blocking ("haze,"
> whatever) filter and the second (with the blue UV markings) with this
> filter removed.

The markings on the flower appeared to be a very vivid deep blue and were 
supposed to be "invisible" to the naked eye.  They looked like runway 
markings for guiding planes into a landing.   

In addition to our idea, Ed Scott suggested taking photopgraphs thru the 
various pass filters and then manipulating them digitally.  Geoff 
returned home from his Latin convention last night and was delighted with 
the idea.  It was immediately elaborated into 2 different methods.  He 
wants to use pictures taken without a haze filter and subtract from that 
a picture taken with a haze 2A. The second idea was to use 5 negatives, 1 
each taken with a uv-pass (18A), blue-pass (47), green-pass (58), 
red-pass (25 or 29 with an ir-cut filter so that only red makes it) and 
ir-pass (87).  These would then be combined.  He is thinking about doing 
this with HIE or Konica.

His big problem is getting the parrot to hold exactly still enough to 
make 5 exposures without moving :-).  It will probably have to be of 
feathers or flowers since they don't get mad and demand a larger bribe 
every minute or so the way the parrot does, generally by flying over and 
grabbing at the camera and photographer.

ZoeJ
 > > Bob Long
> (boblong@xxxxxxxxxxx)
> 

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