IR-cut filter

[David Horn <dh@xxxxxxxxxxxxx>]

> Could anyone advise what filter I could use to make the Konica IR
>film behave more like a normal black & white film? The only filter that I
>have for my T90 is a 25red. I still want to use Konica, but get less of
>an IR look. Would orange be best? 

>Bobbi
Browsing through Kodak "Kodak Filters for Scientific and Technical Uses"
(Kodak Pub. No. B-3H)and it's supplement B-3Ha, I found an "Infrared
Cutoff Filter" No. 301 and 301A. 301A blocks light between about 700nm
and 950mn. The data sheet has a transmittance/wavelength curve. The 301
is a "multilayer dichroic interference-type filter coated on glass. It
reflects what it does not transmit, and hence can be used in projectors
to provide heat protection for the films.
The orange filters listed will probably not help you at all. The book
lists types 16 (yellow-orange), 21 (orange) 22 (deep orange). All have
perfect transmission up to 900nm.
Other filters that cut IR include 52 (light green), 53 (green),54 (deep
green), 94 (blue).
How does the film look with no filter at all?
-- 
David Horn,  Bell Labs Multimedia Communications Research Laboratory
Room 2A-308, 600 Mountain Avenue, Murray Hill, NJ 07974, USA
phone +1 908 582 5533,   Fax +1 908 582 6344, e-mail dh@xxxxxxxxxxxxx

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Topic No. 9