From: Jack Fulton (jefulton1@attbi.com)
Date: 04/09/03-12:06:27 PM Z
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
>> Scott:
>>
>> I don't want to rain on your parade, but it has been my experience
>> that it is almost impossible to raise the true speed of any film - no
>> matter what. I have exposed and developed hundreds, perhaps thousands
>> of rolls of test film. In reality what is usually meant by an
>> "increase in speed" is really an increase in contrast. The point at
>> which the films curve begins to pivot upward does not change, it just
>> gets steeper. I have seen minimal increases in true film speed with a
>> few special additives, pre/post-exposure, and exposing film to certain
>> gas fumes.
>
> Yes to all of the above. About the most *real* increase in effective
> film speed with any developer over the manufacturer's recommendation
> is about 1/3 of a stop. Film speed does increase with CI, however, so
> an effective film speed for a specific film/developer combination
> for printing in silver where the CI needed is about .52 will be less
> than what you will see with the same combination when developing for
> an alternative process where the needed CI is over .70.
>
> Sandy King
>
>
>
>
>
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