Re: one-step direct negative films?

Luis Nadeau (nadeaul@nbnet.nb.ca)
Mon, 6 Mar 1995 21:09:10 +0300

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Maybe in reply to: s carl king: "one-step direct negative films?"

>> Are there any Direct Positive films that have the capability
>> of altering the original's tonal relationships (i.e. increasing
>> the contrast)? I have been threatening to myself to do some
>> testing in these respects, and would appreciate input.
>
>Polagraph will certainly boost contrast. Unfortunately it is a specialized
>emulsion and only available in 35mm and not amenable for processing in standard
>chemicals. Actually, Polagraph and Polapan are more like "reversal" processes
>than Direct Positive ones now that I think of it.
>
>I have never used Kodak's Direct Positive material but would suspect it's
>response could be altered by various development factors.

It is the pre-fogged type. Slow, with a tendency to block highlights and
drop shadow details. It is very easy to adjust the overall contrast, just
by varying development time.

Haven't used it personally for years because of its inherent permanence
problems, i.e., silver migration, which I have seen in the negs I made 15
years ago or so.

Luis Nadeau

>
>andy o o 0 0 o o Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
> \/\/\/\/\/\/ andpph@rit.edu High Speed Photography Lab
>________| |__________________________________________________________

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Maybe in reply to: s carl king: "one-step direct negative films?"