Duplicating a black and white negative as a possitive

[Pete Grange]

[FONT=&quot]I had an idea that I could use a negative film to shoot my negative film in the dark room in order to produce a positive (it would be a negative but a negative of original negative) or so my theory went but am unsure if this is possible and if so how exactly, i had an idea of placing both in contact in the negative holder in the enlarger and exposing it that way, but would be hit and miss on exposure times.

Obviously, I know this would have to be in complete darkness, and the exposure time would be extremely fast, which may be the problem as the enlarger mite not go fast enough even when the aperture is stepped right up

also hello, this is my first post, i appoligise if i am asking what mite seem like an obviosuly stupid question to you, I am after a way to reproduce some 35mm and 6x7 negs as slides ideally with potentially large numbers
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[Dwig]

In theory it would work. In practice, not well. How well depends on what you will use the resulting positive for.

Using a regular camera film won't result in a good positive in the form of a slide. The grey tinted base, alone, will cause the resulting positive to be greyish. Also, the tonal curve of a camera film is not well matched to the task.

Kodak makes a product specifically form making quality positive slides (actually positive movies) from negatives. Its called EASTMAN Fine Grain Release Positive Film 5302/7302. the 5302 number specifies 35mm and the 7302 number 16mm. Its sold only in long rolls. It can be processed in ordinary paper developer (Dektol, ...), handled under safelight just like ordinary enlarging paper and is closer to the speed of fast enlarging paper rather than conventional camera film making exposure easy. It has a clear base and no anti-halation layer to prevent the processed film from being grey.

Check out: KODAK: Print Films: Technical Data: 5302/7302

 

[Pete Grange]

Thanks to the name of that film i have been able to find out alot more on this thank you

i will do this through contact duplication, on an enlarger, i will try it with a high red filter in an atemp to increase contrast. I will also stick some paper int he enlarger to reduce the light and also stop it right up

firstly i will use paper to get a correct exposure thats around 3 or 6 iso, then from that i will use this to work out the time for my film i will duplicate for

and then i will use some high speed developer we have which also increases contrast hoepfully this will work.

I will comment on the results