Re: Aerographic 2424 has a speed of 400 ISO?

[BIELECKJ@xxxxxxxxxxxxxxxxxxxxxxxxxx]

> >The 70mm HIE is actually Kodak Aerographic 2424 ISO 400. It comes in
> >150' rolls which you must spool into cassettes. In the dark, you must
>>then start the film into another cassette and insert both into the back.
>I talked to a Kodak representative and he said that all of Kodak's B&W 
infrared
>film had the same emulsion no matter what the format.  I specfically asked 
him
>if the 70mm Aerographic 2424 had the same emulsion as the 35mm HIE and he 
said
>yes.
>
>If this is true why does Aero. 2424 have an ISO of 400, while 35mm HIE has 
a
>nominal ISO of 200?Do people who use this film actually rate it at 400 or 
do
>you rate it at the same EI as HIE?

With 2424, Kodak doesn't use an ISO rating, they use something called an 
EAFS rating instead (effective aerial film speed).  This rating is 400 and 
is not comparable to an ISO of 400.

>From the Kodak aerial data sheet from 2424, "The characteristics of aerial 
scenes differ markedly from those of ordinary pictorial or ground scenes 
because of the smaller range in subject luminance's, atmospheric haze 
conditions, and other factors.  Therefore, different film-speed parameters 
are used to relate aerial-scene characteristics to practical exposure 
recommendations."
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End of Infrared-Digest V0 #120
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