UV was Re: IR film & X-Rays ?

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

Yep, we've read the information on your web page.  My son printed it out 
and has been carrying it around.  We've been thinking of posting the 
following questions:

Geoff says:
1. I've heard that the wratten 18a is darn near opaque and that only 
about 1% of a flash is UV, so that the exposures have to be really long, 
like 2 to 15 minutes.  Is this right?

2. What film would you recommend for taking UV photography?  I have been 
thinking of Tmax P3200, pushed to something like 25,000.  Does this sound 
reasonable?  What about a color film?

3  I have heard that the sun is the best UV source available so I have 
been planning to take the pictures outside in the sun.  Does this sound 
okay, or would another UV source be better?

4. I figure keeping a bird still for 2 to 15 minutes won't work, so I am 
planning on starting on feathers.  Can anyone think of a way of 
photographing a bird without blinding me and the bird in the process?

5. I have heard the the glass in lenses and the metallic coats fluoresce 
in UV.  Is this true?  A professor I have worked with at the university 
thinks a special lens costing about $2,500 is needed.  Is this true?  To 
get around this, I am think of using an old rollei TLR because there are 
fewer lens elements and the coating seems thinner.  I have also thought 
of using a pinhole camera (this is where the xray film would come in) 
and exposing the stuff for about 8 hours.  I have also heard that 
the fluoresence only happens in the far UV and I am interested in the 
near UV because that is where birds see.  But I guess the film wouldn't 
know that and would still get the UV in the far UV range, right?

6. Anybody got feathers they want to send me?

7. Anybody got a spare 18a to loan in the name of science <grin>?

8. I will also take pictures of the same feathers in IR and visible 
light, also.

9. I have also thought about using a video camera since one like my 
granpere's records down to .8 lumens.  Do camcorders record UV?  Do 
CCD's?  If they do, how is it displayed (if it is recorded wouldn't it 
help much if it only played it back as UV)?

10. And now a question for my sister:  How deep does IR penetrate in 
freshwater?  in saltwater?  How about UV in freshwater?  in saltwater?
What about different colors of visible light?  (she is interested in fish 
vision and when she asked her physics professor he said he didn't know 
and wasn't sure where to look it up).

I appreciate any help or suggestions, including "go look it up yourself", 
if it includes some idea of a good place to start looking.

Thankyou,
Geoffrey Johnson

On Sat, 28 Sep 1996, Willem-Jan Markerink wrote:

> Date: Sat, 28 Sep 1996 19:07:39 +0100
> From: Willem-Jan Markerink <w.j.markerink@xxxxx>
> To: pjohnso@xxxxxxx
> Subject: Re: IR film & X-Rays ?
> 
> On 27 Sep 96 at 5:25, Zoe Paddy Johnson CIRT CSOS wrote:
> 
> 
> > Is the ASA 1600 film sensitive to UV?  My son is looking for some fast 
> > film to do UV photography with for his science fair project on UV 
> > markings on birds.  He'd like to be able to take pictures of something 
> > that moves faster than a feather taped to a piece of cardboard.
> > zoej
> 
> Can't he use flash?
> I have some info about UV photography on my homepage as well:
> http://www.a1.nl/phomepag/markerink/mainpage.htm 
> --
> Bye,
> 
>        _/      _/       _/_/_/_/_/       _/_/_/_/_/
>      _/  _/  _/               _/       _/  _/  _/
>      _/  _/ illem    _/     _/ an    _/  _/  _/ arkerink
>                      _/_/_/  
> 
> 
> 
>       The desire to understand 
> is sometimes far less intelligent than
>      the inability to understand
> 
> 
> <w.j.markerink@xxxxx>
> [note: 'a-one' & 'en-el'!]
> --
> Bye,
> 
>        _/      _/       _/_/_/_/_/       _/_/_/_/_/
>      _/  _/  _/               _/       _/  _/  _/
>      _/  _/ illem    _/     _/ an    _/  _/  _/ arkerink
>                      _/_/_/  
> 
> 
> 
>       The desire to understand 
> is sometimes far less intelligent than
>      the inability to understand
> 
> 
> <w.j.markerink@xxxxx>
> [note: 'a-one' & 'en-el'!]
> 

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

Topic No. 9