Re: M6 & Infra-red

[Bill Welch <Bill.Welch@pressroom.com>]

Colin wrote:
> 
> ROB HEYMAN wrote:
> >
> > > Can anyone solve this for me. When using my M6 with Kodak infra red
> > > B&W film outdoors in bright sunlight I get a circle of higher density
> > > exactly in the centre of the negative.
> >
> > > This, of course, results in a lighter toned area which would cover
> > > about 2cm on a 9x13 print. It appears to happen only when the aperture
> > > is f11 or f16. The circle is quite sharp edged and could be related to
> > > the aperture size. This would seem to indicate that the shutter blind
> > > is not infra-red light-proof.....a disturbing thought.
> >
> > > Has anyone ever had this problem? Can anyone tell me what may be the
> > > cause?
> >
> >    Thanks in advance,
> >
> >    Rob
> 
> Rob,
> 
> I wouldn't expect the shutter curtain to be infra-red proof, it's just
> cloth.  Try keeping a metal lens cap on between shots.
> 
> Have fun,
> 
> Colin

Interesting problem. I don't have an answer, but I think we can rule out 
the cloth shutter being the problem, unless you have a bad one. I've run 
Kodak High Speed Infrared through my old M2 with considerable success and 
no fogging. I didn't even think to use a lens cap. I did get a little 
fogging around the edges of a frame or two when the sun was in the 
picture, as the light/radiation seemed to spill around the edges of the 
frame.

I think I've run the Kodak infrared film through my M6 without problem 
too, but I can't say for certain. Perhaps it was all with the M2. Anyhow, 
let us know what you figure out. 

Bill Welch