Re: Films (and Portra and Thanks)

Hi Stephen,

A technician on the Kodak technical helpline told me that the new
Portra daylight films can take an exposure of up to 10 seconds without
reciprocity failure. The time without failure is longer for Portra
tungsten film. This seemed hard to believe, so I double-checked with
a friend that beta-tests Kodak and other films. His opinion is that
10 seconds is not unreasonable. Its worth a try.

Also, try testing a roll of film in bright daylight. Bracket one or
two scenes widely, like over a six (or more) stop range starting at 1
or 2 seconds, then see which exposure gives the best results. This
will be your basic daylight exposure. Then, increase exposure in
stops (doubles) for various lighting conditions:
Slight Haze.........1 stop.....2x
Light Overcast....2 stops....4x
Heavy Overcast..3 stops....8x, etc.
This test has reciprocity failure built into it, so you don't need to
re-calculate it for each exposure. If you have a light meter, you can
use differences in exposures values to determine the amount of extra
time needed.

Tom

P.S. A month or so ago, I asked the list about their Portra
experiences and would like to thank list members for their helpful
replies. My early "tests" with 4x5 Portra 100T using an 85B filter in
the camera show that it keeps good, natural color up to a minute or
two (didn't get a chance to make any long, long exposures).

----- Original Message -----
From: "Stephen Rowley" <steve@artension.com>

> I am just trying out my newly acquired Zero 2000
> (6x6)
>
> The Kodak site lists exposures longer than one second
> as 'not recommended' for its films.
>
> Could we pool our combined expertise and bring real
> experience to solve the problem.
>
> Steve
>
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Received on Wed Apr 18 10:35:40 2001