From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 04/09/03-05:19:39 PM Z
----- Original Message -----
From: "Jack Fulton" <jefulton1@attbi.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, April 09, 2003 11:06 AM
Subject: Re: Film Speed and Negative Development
> Although I'm not such the tester w/densitometers, tools et
al I do develop
> film and sometimes I do it nicely and at others times just
plain screw up.
>
> Many years ago I used Crone Additive to put in D76 . .
thereby making it
> C76. It did seem to actually add speed. My exposures went
from ISO 400 to
> 600 or slightly above.
>
> With T-Max 400 you can easily shoot it @ 800.
>
> Jack
>
If I remember right Crone additive was just Benzotriazole,
an effective anti-foggant. A very small amount of
anti-foggant in _unused_ D-76 will increase effective film
speed very slightly due to suppression of the slight fog
produced by this developer. For Potassium Bromide the amount
is about 0.5 gram / liter of full strength developer. Some
bromide comes out during development so used developer or
replenished developer already has more than this amount of
bromide in it. More than just this trace will reduce
effective speed by reducing shadow detail somewhat. We are
talking about fractions of a stop.
FWIW, Ilford Microphen is a Phenidone version of D-76. It
will give you slightly greater speed but also slightly
greater grain.
--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com
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