making a positive from a negative

abruzzi · Jul 22, 2021

I've seen numerous threads on this site about chemically processing negative film as a positive. There are kits, or you can buy chemicals yourself. Lots of info and lots of different ways to do it with varing degrees of noxiousness.

What about shooting and developing a shot normally, then in a dark room making a "contact print" but instead of doing it to paper, you do it to another sheet of film? I'm sure many people have tried or done this. Interprositives were a common thing in the cinema world, but I think they had special film developed for that specific purpose.

Anyone who has done this, can you comment on how? What makes a good positive film, low contrast or high contrast? Any special techniques? Or is it a fools errand, and I should just come to terms storing sulphuic acid bleach next to my potassiun ferricyanide? (just kidding)

Oh, and links to good resources would be welcome as well (my searches haven't been fruitful.)

Donald Qualls · Jul 22, 2021

You can't turn a processed negative to a positive in the same film, because the halide that would otherwise have formed the positive image was removed by the fixing step.

A good reversal film is one that reverses well (yes, that's a tautology); ideally including a clear base so Dmin will be very low (to give a "bright" look to the resulting positive image).

There are multiple threads around, fairly recently, about reversal bleaches that don't use sulfuric acid...

abruzzi · Jul 22, 2021

you're misunderstanding what I'm asking. Start with a fully processed negative, place it overtop of a unprocessed, unused piece of film, expose it with light, then put the negative away and normally process the new film. Exactly the way you would make a contact print, but on film instead of paper.

Nodda Duma · Jul 22, 2021

abruzzi said:
you're misunderstanding what I'm asking. Start with a fully processed negative, place it overtop of a unprocessed, unused piece of film, expose it with light, then put the negative away and normally process the new film. Exactly the way you would make a contact print, but on film instead of paper.

This is often done for dry plates. I would expect some film would work for this. Ideally you’d want a higher contrast film (or higher contrast developer) with a clear base. Total guess, but an ortho film might be a good start

abruzzi · Jul 22, 2021

Nodda Duma said:
This can be done for dry plates..plenty of people try this often. I would expect some film would work for this. Ideally you’d want a higher contrast film (or higher contrast developer) with a clear base. Total guess, but an ortho film might be a good start

Thanks, it turns out I have a box of ortho litho that I could experiment with, and it has the advantage of being very cheap and not red sensitive. Only, when I tried shooting it directly, I could never tame the contrast. Maybe it will be more useful in this context.

Pieter12 · Jul 22, 2021

abruzzi said:
Thanks, it turns out I have a box of ortho litho that I could experiment with, and it has the advantage of being very cheap and not red sensitive. Only, when I tried shooting it directly, I could never tame the contrast. Maybe it will be more useful in this context.

Litho is high contrast for graphic arts purposes. You need something like Ilford Ortho Plus.

Nodda Duma · Jul 22, 2021

Pieter12 said:
Litho is high contrast for graphic arts purposes. You need something like Ilford Ortho Plus.

yes. Higher contrast than regular film, but with midtones

Donald Qualls · Jul 22, 2021

You can process ortho litho films to lower contrast by developing in a film-strength developer, rather than print-strength or actual A+B litho film developer. When I was in high school we'd process in print strength Dektol, but that still gave pretty high contrast; I expect something more akin to D-76 would give usable grayscales for printing from a negative. Ilford's Ortho Plus is an alternative, but it might be a little fast for easy contact printing.

cmacd123 · Jul 22, 2021

if you are working 35mm, easiest is movie positive. Like ORWO PF-2 or Eastman x302 (x indicates size and base) FFP and Untrafine often have this spooled down to 100ft rolls.

basically a Blue sensitive contact printing emulsion on a film base.

abruzzi · Jul 22, 2021

I figured the cinema industry had something. Unfortunately my goal is 4x5 at first and maybe 8x10 next. Here is what I'm trying to do...

When I first started shooting 4x5 a couple years ago, I bought a box of Provia 100 just for the heck of it. Some of the shots were stunning, and holding them up to the light was just very very satisfying. I got the idea of placing the the transparency in a double sided glass picture frame and putting it somewhere where it might get a bit of natural backlight. After discussing the idea with a few more experienced people, I was persuaded that it would degrade the image pretty quickly as the UV sucked the life out of the dyes. And of course once its dead, its dead because its the original.

So I thought reversal processing of B&W might last longer since its not just dyes, but actual blacked silver on the sheet. But that may also have a limited lifespan--I don't know--and you'd still be hanging your original so if there is damage the image is lost. So the idea of creating an "interpositive" seems at least a reasonable way to try out this idea--if the constant exposure to New Mexico sun coming in my windows killed it is a year or two, I could always redo it from the original. For this reason, doing it with 35mm isn't going to be that useful, but its interesting to know that it exists in some form.

Donald Qualls · Jul 22, 2021

I'd suggest you start by enlarging onto your existing ortho litho film. In my high school photography course, we did exactly this to make enlarged positives (which were then contact printed to negatives) for special effect like bas-relief prints (this was in 1974-1975, film was the only way to do any of this), overlay printing (project your negative through an internegative), and similar. If you can't get the contrast down far enough, try some Ilford Ortho Plus (it's available in 4x5 and possible 8x10). You can even do this with conventional camera film, but the close you get to films like TMY-2, the more expensive each mistake gets, so start with the cheap ortho litho until you're consistently getting the best results that film can deliver.

Bronson Dugnutt · Jul 22, 2021

Direct positives are possible but the only options of which I'm aware are Harman's direct positive paper, FPP's 35mm Super Positive, and the various instant films (Instax, Impossible, New55, etc)

I may try out some super positive exposed in a camera with a reflective pressure plate to see if I can get any Lippmann-like effects. https://www.jonhilty.com/lippmann

Nicholas Lindan · Jul 22, 2021

The Leitz ELDIA was made for this purpose https://www.shutterbug.com/content/...dia-and-natra-lowest-price-leica-collectibles

Kodak makes 35mm film for making release positives (film for the projector) from a negative shot in a camera - someone who knows about movie stocks should be able to advise.

Keeping the dust down when using an ELDIA is a nightmare.

btaylor · Jul 22, 2021

Echoing what Donald said, I enlarged 35mm negatives to 8x10 Kodalith then backlit them back in a high school photo class. They looked really nice (I was looking for the high contrast look popular at the time). I still have them. I believe there are continuous tone developers you can use with the Kodalith type graphic arts films. Check out Freestyle or Photo Warehouse. It’s fun.

Pieter12 · Jul 22, 2021

Nicholas Lindan said:
The Leitz ELDIA was made for this purpose https://www.shutterbug.com/content/...dia-and-natra-lowest-price-leica-collectibles

Kodak makes 35mm film for making release positives (film for the projector) from a negative shot in a camera - someone who knows about movie stocks should be able to advise.

Keeping the dust down when using an ELDIA is a nightmare.

Not sure, but motion picture print film is almost exclusively color these days (and losing out to digital distribution). You might have to buy a large quantity, too.

Kino · Jul 22, 2021

Contact printed 35mm Kodak 5302/2302 Fine Grain Positive film or ORWO PF-2 processed in Dektol should work just as well, but you're going to have to do some testing to dial it in.

Either stock has around a ISO equivalent of 6 to 12 and is blue sensitive only, so you can process it under a typical paper safelight.

Take an enlarging negative holder, sandwich a known "good" negative with a full range of tones, emulsion to emulsion with the positive stock inside the aperture, stick it in the enlarger and use the enlarger timer to do a series of exposures of the SAME negative of 1, 2, 4, 8 and 16 seconds to start with. Since you can work under a safelight, you can easily notch or mark each frame so they don't overlap.

Process in Dektol or D97 (if you are ambitious) with whatever normal agitation scheme you use for negative with standard stop and fix routines.

When you find the exposure with the MOST correct result, run another more fine-grained series of tests with more precise exposures to determine your best possible outcome.

You can use ND filters over the aperture in the negative carrier if you need longer exposures. Just be sure the filters are spotless!

Mess around with it; it should dial in pretty fast.

Pieter12 · Jul 22, 2021

A thought: scan the negative or use a digital camera to copy it, then make an LVT negative (would then be positive) or invert it and make an inkjet positive on transparent base like Pictorio.

removed account4 · Jul 22, 2021

Donald Qualls said:
I expect something more akin to D-76 would give usable grayscales for printing from a negative.

I watched ortho film processed in HC110 ( can't remember the dilution ). it looked like regular continuous tone film, it was a head scratcher seeing all I ever hear
is people using ortho litho and print developer and fighting contrast and fog... was really strange

cmacd123 · Jul 22, 2021

jnantz said:
I watched ortho film processed in HC110 ( can't remember the dilution ). it looked like regular continuous tone film, ------ I ever hear
is people using ortho litho and print developer and fighting contrast and fog... was really strange

I supect that it is easy for folks to mix up "ortho"and "Litho" and assume that they are always the same thing. some ORTHO film are continuous tone, others are intended for very high contrast (LITHO) use. the Litho developes tend to be designed to make ANY film have high contrast.

cmacd123 · Jul 22, 2021

Kino said:
Contact printed 35mm Kodak 5302/2302 Fine Grain Positive film or ORWO PF-2 processed in Dektol should work just as well, but you're going to have to do some testing to dial it in..

yes, dektol or your favorite print developer is the way to go for the home user it is too bad that only the colour print film (2383) is made in 70mm perforated 65mm format. I understand that the 5302 version is now defunct as Movie prints are invariably on estar these days. the ORWO is probably also only on Polyester.

PF2 or 2302 is only blue sensitive so it should work under any B&W enlarging paper safe-light. I recall, (it has been years) that the image in the developer must be very much darker that seems possible for it to not look thin, once fixed and viewed by Trans-illumination.

Kino · Jul 22, 2021

cmacd123 said:
yes, dektol or your favorite print developer is the way to go for the home user it is too bad that only the colour print film (2383) is made in 70mm perforated 65mm format. I understand that the 5302 version is now defunct as Movie prints are invariably on estar these days. the ORWO is probably also only on Polyester.

PF2 or 2302 is only blue sensitive so it should work under any B&W enlarging paper safe-light. I recall, (it has been years) that the image in the developer must be very much darker that seems possible for it to not look thin, once fixed and viewed by Trans-illumination.

Exactly! Dmax should be around 2.90 transmitted on a "normal" negative with good shadows.

DREW WILEY · Jul 22, 2021

It's easy to do. My favorite films for either contact or projection negative to positive inversion are FP4 and TMax100 (TMax is one stop faster). Don't use litho film; it's a pain in the butt. Any common b&w FILM developer can be used to process the positive duplicate. But I now mostly use HC-110 for that specific purpose. Don't use Dektol. Gosh, some people sure do things the hard way!

To determine the correct exposure time, sacrifice a sheet and just do a simple test just like you would with an enlarging paper test strip using a card for progressive amounts of exposure. Use your enlarger itself as the light source, preferably at a somewhat smaller aperture opening to get more of a point light source effect. It will take a little experimentation, but this doesn't involve anything complicated.

Kino · Jul 22, 2021

If you use Cine film and you want good projection contrast, you need the energy of Dektol or D97.

abruzzi · Jul 23, 2021

DREW WILEY said:
It's easy to do. My favorite films for either contact or projection negative to positive inversion are FP4 and TMax100 (TMax is one stop faster). Don't use litho film; it's a pain in the butt. Any common b&w FILM developer can be used to process the positive duplicate. But I now mostly use HC-110 for that specific purpose.

Thanks! This would certainly make parts of the process much simpler. The only negative is with ortho flm I could use a safelight, using pan film would require complete darkness which is a bit more difficult for me. Being diabetic the sense of touch in my finger tips isn't what it once was so properly aligning two 4x5 sheets on an 8x10 piece of glass will be a little tricky. Do you see any reason I couldn't insert both sheets into one of those single sheet printfile sleeves, then put that on the contact print frame? The manufacturer says you can print contact prints through the printfile sleeve, but I don't know if it potentially causes issues? The only think I can think of is if the plastic get a crease and distorts the light right before hitting the film, but anything else to worry about if I try it that way?

DREW WILEY · Jul 23, 2021

I think that if you used a print profile sleeve you'd get Newton rings and other visual anomalies. The kind of "contact printing" the marketers of that kind of thing have in mind is only for the most casual kind of proofing purposes. A real contact printing frame would be better, especially if it contains Anti-Newton glass. And of course, real ortho sheet film could be used. But high contrast ortho litho style will be difficult to control and frustrating to develop. I happen to use a pin-registered printing frame in conjunction with a precision punch. But it should be easy enough to tape the two sheets to glass into approximately the same position, especially if you're doing this via red safe light.

making a positive from a negative

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