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Lack of antihalation layer

  • From: "Thomas H. Hogan" <flzhgn@xxxxxxxxxxxxx>
  • Subject: Lack of antihalation layer
  • Date: Mon, 17 Feb 1997 08:22:55 -0800
Isn't the reason for not having an antihalation layer simply to 
make a truly high speed film with infrared sensitivity way out
to the 900 wavelengths?  Maybe those longer wavelength infrared photons
don't pack the same punch as visible light photons.

In the old days the infrared glass plate negative required extremely
long
exposure times or the emulsion was hypersensitized with either ammonia
gas or a solution of that poisonous ingredient of sewer gas,
triethanolamine. This helped to get infrared wavelengths out to 850
nanometers.

Kodak high speed infrared film has five times the speed of the old stuff
Perhaps, if there were an antihalation layer it might not be so
sensitive
to the infrared wavelenghts in the 800 to 900 nanometer range.
If you want the antihalation layer you could use the Konica 750
Infrared!

Thomas H. Hogan <http://www.pic.net/~flzhgn/>

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End of INFRARED-PHOTOGRAPHY Digest 212
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