Re: Fw: IR 750 Sensitivity

[Dan Cardish <dcardish@xxxxxxxxxxxx>]

Just make certain that the green inanimate object is really just green.
Try doing tests using a wratten green cutoff filter (I've forgotten the
number, is it 58?)

Dan C.

At 08:07 AM 07-11-00 -0700, Christina Z. Anderson wrote:
>     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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