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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.

jnanian
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.

jnanian
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

peter schrager
8-Jun-2017, 18:24
Thanks for the advice Peter. ZZ medical sales dupe xray film. Do you know what developer will be the best?

Thanks
Bill
I used very dilute HC-110 reason being it is always the same energy in the dilution and with other developers you never know

rknewcomb
8-Jun-2017, 19:26
[QUOTE=jnanian;1394054]hi bill

i set the bar low so i am always happy :)

I just love this quote, such a wise point of view.
Think I'll get it printed on a T-shirt.

Robert

Goldman
8-Jun-2017, 20:28
John, Thanks for the perfect explanation.

Bill

jnanian
9-Jun-2017, 05:59
bill and robert

glad i could help :)

gudageo
1-Jul-2017, 11:42
Coping on Litho, X-ray and such contrast films is a bit complicate and needs to work a lot with loses of film, different developers, time... You need a big patience and finally acceptable results will come. However special purpose film exists, which has wide tonality, very fine granularity and is very easy to work with under safe red light (you can control developing process on all stages). People uses it also for direct photographic process too successfully. Just google: Agfa Avitone P3p Orthochromatic BW film and you find it with appropriate instructions in different size options.

Drew Wiley
1-Jul-2017, 14:48
It's easy. Contact your original shot emulsion to emulsion to your interpositive, which you should slightly overexpose but under-develop. Then generate your printing dupe developed to normal contrast. I like to use FP4 for both steps. I just pulled a new shot from the film washer a few minutes ago which I want to print reverse-tonality, so plan to make a normal-contrast contact interpositive from it.

peter schrager
1-Jul-2017, 16:29
Coping on Litho, X-ray and such contrast films is a bit complicate and needs to work a lot with loses of film, different developers, time... You need a big patience and finally acceptable results will come. However special purpose film exists, which has wide tonality, very fine granularity and is very easy to work with under safe red light (you can control developing process on all stages). People uses it also for direct photographic process too successfully. Just google: Agfa Avitone P3p Orthochromatic BW film and you find it with appropriate instructions in different size options.
THANKS for the tip!!

Goldman
2-Jul-2017, 15:57
I read the PDF info and it seems to be a great way to make the black and white duplicate. Do you know who have this film for sale in North America?

Thanks
Bill

BetterSense
2-Jul-2017, 19:07
I have always heard that repeat duping increases contrast. Why? Since film is normally developed to .5 or .6 contrast, I would expect duping to decrease contrast since 0.5*0.5<1. What am I missing?

gudageo
3-Jul-2017, 02:54
I read the PDF info and it seems to be a great way to make the black and white duplicate. Do you know who have this film for sale in North America?

Thanks
Bill

I am almost sure that nobody have. I have this film listed on ebay during last year and never seen other selling in the net. Excuse me, if informing of the people about my commercial interest does not seems honest, but interest is mutual as I see. This type of film is discontinued and information is very pure. I sell them trimmed and packed in 4x5 and 8x10 formats from original 10x10 in. boxes. I have sold a lot of film until today and buyers like them - you can judge from feedback yourself.
...And sorry for my English :)

EdWorkman
3-Jul-2017, 07:59
SO-132 is long [decades]gone. Xray dupe is available, as noted above. It is a lot slower than SO-132.
I have used XRD to enlarge negs by projection.
Exposure times under a Beseler 8x10 cold light are long, but dodging and burning is poosible.
Contrast may be 'controlled' [ that is, with a lot of experimentation] by varying exposure and development time.
I have used the interneg process to dupe old negs that have yellow, well goobers is the best term- not just a stain.
First make a positive on a pancromatic film. Then make the new neg on ortho or pan.
Continuous tone ortho is nice because it can be worked with under the safelight, pan needs total dark
Hi contrast ortho is only a PITA for this use onnacounta it raises contrast or is very tricky to avoid same.

Rich14
3-Jul-2017, 08:41
I have always heard that repeat duping increases contrast. Why? Since film is normally developed to .5 or .6 contrast, I would expect duping to decrease contrast since 0.5*0.5<1. What am I missing?

Getting increased contrast with each succeeding "dupe" is a bit of a misnomer as far as actual increased contrast of the dupe film material itself. The film doesn't increase in contrast but the image does. Here's what happens with a transparency (color slide). A similar effect happens with negatives:

The first generation image (original slide) is able to capture a finite range of luminance values from the scene. The original scene has a range in excess of 100,000:1 or >15 f/ stops, >4.5 O.D.

Let's say the film is able to capture a range of "6 stops" from the original 15. (Color reversal films typically have a dynamic range of 5 stops, maybe 6)

The slide is then trans-illuminated for scanning, or for duping onto another piece of film. The range of luminance values of the light coming through the slide material itself is a little greater than 1000:1 (about 10 stops or 3.3 O.D.) There are only 6 "stops" of original scene information on the slide, but that information is being presented to a scanner sensor or the duping film in a range of light values of a little more than 1000:1 (about 10 stops or 3.0 O.D.). This is why drum scanners advertise their dynamic range capability of about 3.5-4 O.D. (They don't really reach that - they all crap out at about 3.0-3.2, but that's a whole other story).

Duping film (when it was still being made) was a "lower contrast" material than slide film. It had a slightly greater dynamic range. But not 10 stops. So some part of the 1000:1 light range coming through the original slide gets chopped off. Highlights or shadows, or both.

Let's pick both. Some very dark, but not black value of the original gets mapped to black on the dupe. Some very light, but not white value on the original gets mapped to the dupe's white. All other values stretch out to "fill in" between the new extremes.

The result looks like a higher contrast version of the original scene. If the dupe is duped, the contrast goes through the roof.

Rich

bob carnie
3-Jul-2017, 09:25
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

I make enlarged negatives on Ilford ortho using a Durst Lambda for direct silver contact, pt pd and gum, you need to do a high resolution scan but after that any size up to 28 x40 inch is available(larger sizes quote only)
I am doing 16 x20 now and you could gang up a few negs ..