Re: [ATM] Zernike (or Lyot) phase contrast tests

[Mark Holm <mdholm@telerama.com>]

Don't know if Ektagraphic HC is still available.  Kodak Technical Pan 
2415 is and will give very high contrast and even higher resolution than 
Ektagraphic HC  2415 can be ordered from mail order photo supply houses 
like Calumet, Adorama, B&H, etc.  ASA is about 25 depending a bit on 
processing.  Almost any ordinary baldk and white processing will result 
in very high contrast with 2415.  .More normal contrast can be had with 
a special developer. Kodak Technidol, or with a home brew developer 
called POTA or with Kodak's newest black and white developer XTOL.  
Various concentrations of Kodak HC-110 developer can give contrasts 
sonewhat intermediate between "normal" and very high.


Developing black and white film isn't hard, and doesn't require a lot of 
equipment, if you are only going to develop the negatives, and not print 
them.  The main equipment you need is a developing tank and reel.  About 
$30 plus shipping from one of the mail order houses.  Any public library 
should have books that can instruct you on the technique.  The big 
requirement is an absolutely dark room for loading the film from the 
cassette onto the develping reel.  A windowless bathroom can usually be 
made temporarily dark enough with a little application of dark towels 
and sheets, or duct tape around the light leaks in the door.  A gadget 
called a film changing bag will let you do the job in a normally lit room.

On the other hand, a digital camera would probably give shorter 
exposures, and you can manipulate the contrast freely with most photo 
editing software.

Mark Holm
mdholm@telerama.com
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