Black and White Duplicate Negative

**Goldman** · 8-Jun-2017, 09:35

I would like to produce a duplicate of 4x5 and 8x10 black and white negative. First I did a contact copy of my original film negative and it turns a positive. The positive is sharp and has normal contrast. Then I contact the positive and it turned to be negative. This dup negative is very contrast. I used Arista Ortho Litho film, Efke print film, and X-ray film and processes it with different developers. The result is the same high contrast.
I would like to use the negative for cyanotype print.
Is it a way to get a good normal contrast duplicate negative?

Thanks
Bill

**Jim Noel** · 8-Jun-2017, 09:57

Each time a negative is reproduced in this manner, it will gain contrast. The contrast must be controlled at each step through exposure and development.

**jim10219** · 8-Jun-2017, 12:27

Probably the best way is to scan it into a computer and then print it onto a transparency. I've got a good bit of experience with cyanotypes and often times what makes a good silver print doesn't do so well with cyanotype, as far as negatives go. You'll usually have to adjust the contrast pretty good to get a decent cyanotype. And that's most easily done in Photoshop using the curves tool.

However, you may be looking to avoid going the computer route for personal/artistic reasons. If so, that's cool. But, in my opinion, the best way to make alternate process prints is with computer generated negatives so you can standardize and control just about everything. It cuts down on a lot of time and money wasted experimenting with the same print over and over again while you search for the perfect balance of process.

**jnantz** · 8-Jun-2017, 12:59

bill:

photowarehouse ( ultrafine ) used to sell ( maybe they still do ? )
what was used to be sold as SO-132 ( kodak's professional duplicating film )
but their own packaging, and it worked OK for what it was.
you contact print your negative on it, and you get a negative, it was
( is? ) single step film. so you get a negative, not a positive.
it was slow like azo slow ... and maybe if you can scare some up it will work for you?
otherwise i would invert a scan, adjust your contrast ( as already suggested ) and bring your film
scan to a xerox shop and get OHP prints made for like 75¢ each. that is what i am doing these days
and it works great ..

YMMV of course.

good luck !
john

**peter schrager** · 8-Jun-2017, 17:31

there is also xray dupe film if you can find any

**Goldman** · 8-Jun-2017, 18:00

Thanks for advice John. I now remember that I have used SO-132 but I didn't know where to get it from. I also like to try to scan and print at the Xerox shop.
Some questions: I am from Canada and don't know where to find the Xerox shop. Is it the place that uses Xerox photo copy?
And sorry for the last stupid question: What does it mean "OHP" and "YMMV"

Thanks
Bill

**Goldman** · 8-Jun-2017, 18:02

Thanks for the advice Peter. ZZ medical sales dupe xray film. Do you know what developer will be the best?

Thanks
Bill

**Eric Woodbury** · 8-Jun-2017, 18:19

SO-132 is gone.

The best results I've seen for such an endeavor was done by making a 'perfect print', then re-photo in the size of choice with your most linear film/developer combo. With luck, you get a perfect negative.

**jnantz** · 8-Jun-2017, 18:20

hi bill

sorry for that ..

a copy shop like kinkos, copy cop &c. i used xerox as a generic word, like kleenex. or cheetos ..
at least near me they can make a transparancy on overhead transparency film ( OHP = overhead projection film )
and it costs about 75 cents ... ymmv - your actual mileage may vary
as in " here at the auto factory your huummer will get 75 miles per gallon city 100 miles per gallon highway
but your actual mileage may vary from our factory conditions ( you may get 3 miles per gallon highway and 1 mile per gallon city )
its kind of a disclaimer in case your copy shop sells the over head transparancy film for 3$ each and your results are terrible
because you don't set the bar as low as me, i set the bar low so i am always happy

best of luck making your copies !
john