Re: Ilford SFX 120 & personnal info

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On  7 Jan 99 at 18:44, George L Smyth wrote:

> Jean-Francois Neron wrote:
> > 
> > I just bought some Ilford SFX 120 film and would like to know for what ISO
> > I should set my camera. I'll use a Tiffen 25 Red filter.
> > 
> > Also is using a #29 red filter making a big difference? I've never used any
> > infra-red film before.
> 
> Actually, SFX is an extended-red film, not an infrared film.  There shouldn't be
> much difference between a #25 and #29 filter.  I don't remember the EI at which
> I shot the film when I tried it (I wasn't too impressed with it), but thinking
> back I believe that if you knock 1/3 to 2/3 stops from the suggested speed you
> should get proper negatives.

Especially with these pseudo-IR films, the difference at the end of
the sensitivity scale is large....#25 is not very exiting, while #70
or even #89B starts showing the Wood-effect nicely (which on itself
is not IR, as it starts at 695nm, while the visual limit is
780nm....that's why I call it 'pseudo-IR', as the Wood-effect is the
main ingredient of Kodak/Konica, visual limit or not). 

Btw, I can offer #29 and #89B in thin polyester foil qualities, for
those wanting to make homebrew of BTFR (between the film rails)
filters....US$0.50 pro square centimeter....if anyone wants details, 
mail me privately.

--                 
Bye,

Willem-Jan Markerink


      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
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