Re: Darkloading

[George L Smyth <GLSmyth@xxxxxxx>]

Willem-Jan Markerink wrote:
> 
> On  9 Aug 96 at 23:47, George L Smyth wrote:
> 
> > Willem-Jan Markerink wrote:
> >
> > > Nope, only the Konica has a real blind spot in the green; the Kodak
> > > shows a rather stead line across the spectrum (HIE and IE share
> > > almost the same spectral sensitivity btw).
> >
> > Wrong, there's a marked dip in the spectral sensitivity on Kodak's film
> > around 520nm.
> 
> Yep, but the dip is hardly enough to warrant a solution for the
> fogging only for that reason.

No argument there.

> And the dip as such in that area is also not special, even an Ilford
> FP4 shows a dip slightly earlier.

Pretty much all films do this because of the natural sensitization
combined with the extended sensitization.  Near impossible to get a
straight line.

> The Konica shows two separate areas of sensitivity, one peaking at
> 440nm, and one at 740nm. Between 520 and 660nm, the sensitivity is
> nil.

Well, don't put too much stock in the documentation that Konica sent
you.  If you look again, you'll notice that both indicies aren't
labeled.  What appears to indicate a lack of sensitivity is merely where
the curve falls off the chart.  Were the vertical coordinate labeled (as
it should have been) and the chart extended to include the full line,
I'm sure we'd see sensitization in that area.  

george

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Topic No. 2