Re: Horizon 202 / HIE- strange fogging problem

["Keith Davison" <keith.davison@xxxxxxxxx>]

> On 26 Aug 99 at 10:37, Keith Davison wrote:
> 
> > When I use Kodak HIE in my Horizon 202 I get a strange pattern of "fogging" 
> > on the film. 
> > The "fogging" appears as a stripe of very dark fog starting at the begining of 
> > the film and running for about 6 Horizon frames, this stripe is located along 
> > the bottom edge of the film (top edge in the camera), and is very dense near 
> > the edge, fading to nothing just before the frame edge begins.  This stripe 
> > also gradually fades in intensity as it runs along the film, disappearing, as I 
> > have said, by Horizon frame 6.  This "fogging" is very puzzling, I could buy a 
> > light leak in the Horizon, but why does it only affect the first six frames of 
> > every film?  To my certain knowledge the last roll of HIE through the Horizon 
> > was used in very bright sunlight for it's last ten frames, but no light leaks 
> > appear on that section of the film.  HIE from the same batch, used in my 
> > conventional 35mm bodies shows no fogging at all.  Colour negative film put 
> > through the Horizon is also fog free.
> > I am using a homemade 87C filter, the film is darkloaded, and I process in 
> > Xtol 1+1. 
> > This problem does not affect image quality at all, but I am curious as to its 
> > cause, any ideas?
> 
> Quick & dirty guess: 
> You are using a darkload bag that is not perfectly IR-proof....
> While this might not show with other bodies, you are fiddling much 
> longer with the 202 inside that bag (or inside a dark room that seems 
> dark for those other bodies).
> 
> The fogging is very typical for darkload/darkremoval of film and 
> light hitting the cannister....either visible or IR-only.
> 
> Btw, do you process it yourself?
> If a shop handles the cannisters, even with the film leader
> retracted inside, in daylight, the effect is almost the same.
> 
> 
> --                 
> Bye,
> 
> Willem-Jan Markerink


Nope, I load my bodies in a changing bag in my darkroom, also the fogging 
pattern (one edge only), is too repeatedly specific for this kind of cause.  I 
process my own film and for IR, I load my spirals in a changing bag in the 
darkroom also.
My latest best guess is a light leak down the shaft of the take up spool.  
There is no flange on the upper end of the spool, so any leakage down the 
shaft would hit the wound edge of the film.  This would explain why only one 
edge of the first six frames is affected, as the film winds on to the spool the 
diameter increases, gradually taking later film out of the leak area, the lack 
of anti-halation coating would cause the gradual fading of the fogging, and 
this theory also fits the "edge darker" nature of the fogging.  
Do you know what the light trapping arrangement for the takeup spool shaft 
is?  Might be worth opening the case up to see if I can improve it.
Cheers,

Keith Davison
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