Re: Fw: IR 750 Sensitivity

["Christina Z. Anderson" <tracez@xxxxxxx>]

     Yeah, Dan, on my sheet the graph shows two humps and no _anything_ at
the green part of the spectrum; the question has been is it "low
sensitivity" as you say or "blindness" as two books say, and now Konica
says, as in the attached post below.
     So this morning I woke up with a possible answer--others dream nice
dreams and I am trying to figure out why the Konica company says Konica 750
is "blind" to green light instead of saying it is "less sensitive" and I got
it:  check me out and see if this is not right:  of course trees (green) do
not turn clear (black on a print) on Konica film (one reason given for
disproof of its green blindness) because they always reflect IR light,
right, even without a red filter on the camera they are still going to
reflect IR light and affect the film, correct?  So the only way to really
test this theory is to take a green inanimate object and theoretically take
a picture of it where there would be no IR light available and see if the
negative is clear where the green object is.  Maybe it isn't possible to
take all IR waves out of light (Andrew D. you could answer this one; aren't
you proficient in the science of photography?) so therefore, technically, it
would be impossible to see something green/unlighted render a clear
negative.  Therefore, Konica could be right.  Just that it doesn't really
mount to a hill of beans, anyway, as far as film exposure goes, unless the
IR is low and you are photographing an entire green wall or some such thing.
OK I'll stop on this thread, as no one probably gives a hoot! OH, maybe when
I get Rolland's HIE in the mail I can go out and shoot green things with
both the HIE and Konica and see if there is a dif. On second thought, that
would be a bit expensive...
Chris
> I have a data sheet lying around somewhere which showed quite clearly a
low
> spot around green on a spectral sensetivity curve for Konica 750.
>
> Dan C.
>
> At 10:32 PM 06-11-00 -0500, ADavidhazy wrote:
> >> OK, list; here's the answer I finally got; Andy Davidhazy, what do you
make
> >> of this???  Hey, I'll let you be the one to process it under a green
light
> >> and tell me if it gets fogged or not. Me, I'll just not trust it...
> >> Chris
> >
> >Veeerrrryyy interesting. Just remember that I claimed to have made this
> >deduction, based on postings on this list, first!   ;-)  call it the
> Davidhazy
> >and Company safelight processing guide for Konica 750 film!
> >
> >BTW, please note that even if this IS true (which I very much doubt) you
> would
> >need an IR absorbing filter in addition to the green filter to use as a
> >safelight ... unless the green filter one happens to get is opaque to red
and
> >very near IR ... as well as to blue of course.
> >
> >adios,
> >
> >Andrew  o o  0 0 o . o  Davidhazy, Imaging and Photo Tech
> >         \/\/\/\/\/\/          http://www.rit.edu/~andpph
> >__________|        |_____________________________________
> >
> >
> >> ----- Original Message -----
> >> From: Todd Tereshkow <Tereshkow_T@xxxxxxxxxx>
> >> To: <tracez@xxxxxxx>
> >> Sent: Monday, November 06, 2000 6:09 PM
> >> Subject: IR 750 Sensitivity
> >
> >> > Christina,
> >> >
> >> > Thank you for your interest in Konica IR750 film.  The film
> >> > is essentially blind in the green part of the spectrum.  The red
filter
> >> will
> >> > give you the most vivid IR effect compared to the orange filter.  I
would
> >> > recommend that you experiment with both filters and bracket the
exposure
> >> to
> >> > find the appropriate exposure level and IR effect that you are
looking
> >> for.
> >> >
> >> > Regards,
> >> >
> >> > Todd O. Tereshkow
> >> > Vice President Technical Service
> >> > Konica Photo Imaging
> >> > 725 Darlington Avenue
> >> > Mahwah, NJ  07430
> >> >
> >> > Phone: (201)574-4070 E-Mail:  tereshkow_t@xxxxxxxxxx
> >> > <tereshkow_t@xxxxxxxxxx>
> >> >
> >> >
> >> >
> >> > -----Original Message-----
> >> > From: Christina Z. Anderson [mailto:tracez@xxxxxxx]
> >> > <mailto:[mailto:tracez@xxxxxxx]>  <mailto:
> >> > Sent: Friday, October 27, 2000 10:41 AM
> >> > To: film@xxxxxxxxxx <mailto:film@xxxxxxxxxx>
> >> > Subject: Konica 750 spectral sensitivity
> >> >
> >> > I've been trying to call tech help and can't seem to locate the
correct
> >> > place!.  I have your technical data sheet with the graph of spectral
> >> > sensitivity of Konica 750 Infrared.  My question is this: is it BLIND
to
> >> > yellow and green light waves, as the graph looks like it shows, or is
it
> >> > just less sensitive in this area between 520nm and 650nm?  Do you get
> >> equal
> >> > results with the orange 15/16, red 25 and red 29 filters therefore?
> >> > Thanks in advance
> >> > Chris Anderson
> >> > PS I know you are discontinuing this film but I have it
> >> > still.
> >> >
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