HIE in a Canon T90

[Ian D Wilson <idw@xxxxxxxxxxxxxxx>]

Does anyone else out there use HIE in a Canon T90?  Up to now, I have
always used one of my (metal bodied) A1s for HIE, but I tried a roll
recently in my T90.  There have been many messages to this list,
dispelling the "urban myths" about polycarbonate-bodied cameras and film
viewing windows; I was surprised, therefore, to find that the film had
been fogged in a very consistent way.

Every frame has a vertical line of fogging about 1/3 of the way across,
with a very sharp cut-off. The line is worse at one side of the frame
than the other, but is it certainly present all the way across.  Given
the anatomy of the T90, the light-trap of the film canister is just to
the right of the viewing window (when viewed from the back).  My guess
is that the viewing window leaks IR, and fogs the film which has just
been unwound from the canister - in other words, the frame *before* the
one which is being exposed.  (The sharp cut-off in the fogging must
represent where the film disappears into the light-trap of the
canister.)  Also, the amount of fogging appears to be dependent on two
factors: (a) the brightness of the day during which the pictures were
taken; and (b) the length of time between each frame.  Dull days and
rapid firing seem to minimise the fogging.

Is this just my T90 which is playing up, or has anyone else seen the
problem?  Until I can get it sorted, I guess I'll stick to my trusty
A1s!

- -- Ian.

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Dr Ian D. Wilson         |  Email:  iwilson@xxxxxxxxxxxxxxx
Principal Engineer       |  WWW:    http://www.telemedia.co.uk
Telemedia Systems Ltd.   |  Tel:    +44 (0) 1223-477000
Mount Pleasant House     |  DDI:    +44 (0) 1223-578378
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