Re: HIE light leakage

["Jason Revell (in5)" <jason.revell@xxxxxxxxx>]

Surely if it is the felt trap that is not IR opaque, but visible opaque
it would
surely be safe to load the film in light as long as there was no IR
light about,
light for instance under dim fluorescent lighting?  I know the
'exposure' time
would be quite long but would it make enough of a difference?  Has
anyone
had any experience with this or willing to try?  :-)  This could perhaps
explain
why sometimes people have loaded it O.K. under very subdued lighting.

I still remain convinced that is primarily due to the anti halo layer.
As this
'prevents' reflected light from the pressure plate affecting the film.
It must
therefore, when wound around the cassette, prevent the light traveling
to the
emulsion which is wound on the inner side of the cassette.

This does not explain why this is not the case with 70mm, but I have
never
had the luxury of being able to afford a 70mm back for my RB.

Jason Revell
jason.revell@xxxxxxxxx


 ----------
From: George L Smyth
To: infrared@xxxxx
Subject: Re: HIE light leakage
Date: Tuesday, 27 January, 1998 22:31

There are two reasons for the loading requirement.  One is that the felt
trap in
the HIE cassette is not IR opaque.  The other is that HIE film does not
have an
anti-halation backing, which allows light piping.  This is in reference
to 35mm
cassettes, so I can't speak to 70mm.  I got this information from one of
Kodak's
IR gurus.

george

 --
 Handmade Photographic Images
  http://www2.ari.net/glsmyth/
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