4x5 Internegative

I'm going to try to make a 4x5 internegative from a slide so I can make a color print, and I was wondering how that is done? Is it a contact print of the slide onto negative film? How do you hold them together? I have some contract print frames that would work. Or, I can see putting them together into a 4x5 enlarger frame. How would you expose it? I'm just wondering about the mechanical aspect of the process. I can see a couple of possibilities here that might work, or might be impractical depending on the exposure requirements.

Presumably the transparency film is 135 format, if so, the simplest way is to project the image using an enlarger onto the 4x5" C41 film which is held in place using an enlarging easel.

Obviously everything is done in total darkness, so you'll need to get things in order to achieve good positioning.

You may wish to practise with B&W film first to get technique right, then move onto colour negative.

Whenever you duplicate, or transfer an image from one piece of film onto another, you will end up with a contrast kick and as transparency film is often high in contrast, this could be an issue. Kodak used to manufacture C41 duplicating film, C41 Color Print film (which is made to give you a transparency from a colour negative and used to make print film for cinema projection). Both of these were available in 135 and 4x5 format among other sizes, but no longer available today to the best of my knowledge.

You may have issues with the Tungsten light source of your enlarger giving a colour cast to the C41 colour film you are projecting onto. We actually had a colour correction filter below the lens on the enlarger for this issue. It could be possible to use filtration in the colour head.

Doing duplication work under an enlarger is fraught with dust issues, in my own darkroom I have a compressor with a water filter and a dust filter for the air. The unexposed film was placed in the easel and taped on one of the short sides, I then gently lifted the film while at the same time turning on the air to gently blow firstly underneath the film, then over the top of the film once it was flat. This did to a certain extent remove most of the dust, but within reason, never 100%.

Around once a month for around 10 years I used this process to enlarge onto 4x5" colour negative film; it was a very rewarding but sometimes quite frustrating time.

Contact printing works well, dust issues are about the same, using a vacuum easel works best. Simplest method is a sheet of glass on the top, but vacuum is better.

Mick Fagan said:

Presumably the transparency film is 135 format, if so, the simplest way is to project the image using an enlarger onto the 4x5" C41 film which is held in place using an enlarging easel.

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No, actually. The transparency is 4x5. If it were 135 or 120, I'd just use a slide duplicator and maintain format. I have a ton of 4x5 reversal and some internegative.

If I'm doing a contact print, I wouldn't really need to use my enlarger head. I could use a flash, which, I'm guessing might be more appropriate if I end up using regular negative film. I just have no idea about the exposure amount or timing, or how reciprocity might be a factor if I use the enlarger. I just want to get some sense of the process before I get started.

We used to produce 5"x4" Internegatives by projection ( De Vere 504 ) from all formats between 35mm cine ( half frame ) to 5"x4".
The film was loaded in double-darkslides and held 'in register' in the corner of a standard enlarging easel.

Never had dust problems, but just before exposure open the darkslide, give the sheet a quick blast of air and hit the expose button.
Although I've never produced colour internegatives with camera film, I'd strongly suggest using ND filters in the lamphouse to cut down light levels, and colour correction filter ( if needed ) and pull the process by -1 stop.
Plenty of tests needed to set up though !

John S

You could try either pre or post-flashing the dupe negative by loading it in a standard 4x5 holder and using a camera to lower contrast.

It would have to be a very small percentage of the entire exposure on a totally smooth and evenly lighted target, but the camera shutter should be able to give you that in a very controlled manner. Of course, color temperature of the light would be important as well.

Maybe you could turn the enlarger to the wall and use the same lamp and filtration used to make the actual duplication exposure to keep it all the same color temp.

This would add a pretty substantial layer of testing to the basic duplication process, so you might only consider this process AFTER you get a relatively successful dupe negative made and the contrast is still too high.

Pre-flashing is probably a bit more predictable than post-flashing, due to the interaction of the latent image with the post-flash exposure, but only testing would determine which is the best.

Just a thought...

You know, it also occurs to me you could also try bi-packing the 4x5 slide with the dupe neg stock, emulsion to emulsion, in a 4x5 film holder and a field or monorail camera for all operations; exposure and flashing with the same light source.

It might take some doing to modify a 4x5 film holder, not really sure about that, but the camera's shutter and the light-tight nature of the film holder would seem to make the process much more predictable and offer more control.

In fact, you could probably use a 4x5 contact printing frame in the gate, which would solve the modifying a 4x5 film holder problem...

Since you are not forming an actual image (actually you would want to AVOID forming an image on the bi-pack), focal plane would not matter at all as long as the illumination over the aperture is even.

Kino said:

You know, it also occurs to me you could also try bi-packing the 4x5 slide with the dupe neg stock, emulsion to emulsion, in a 4x5 film holder and a field or monorail camera for all operations; exposure and flashing with the same light source.

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I considered this possibility. I also envisoned something similar, maybe with frosted white glass and a dark slide, that would hold the two together. I could then expose under a controlled source, either my color head or a flash.

I've been doing a lot of work with acrylic lately, and it seems that it shouldn't be too hard to make something that would work.

I presume you mean a color interneg for sake of RA4 printing? It can be done in a very high quality manner using current films, either by contact or enlargement onto sheet film, but there's a steep learning curve to it. I recommend the enlargement method with 35mm originals. You need your colorhead set to around 5000K using a good color temp meter. Use Portra 160 sheet film. The original should be between AN glass in the neg carrier, and preferably registered to an unsharp contrast-reducing masks (a big topic in its own right). The color neg sheet film should be in a sheet film holder firmly attached to the baseboard, and the lens set for an exposure time around 10 seconds (determined via trial and error, unless your really want this to become a complicated discussion).

Flashing can hypothetically be used to mitigate contrast gain in lieu of masking. I personally prefer the latter. But either way, it would take a much more extended discussion than I have time for now.

That will at least allow you to swing at the ball a few hundred times and hope to hit one. But with enough experience and some serious instrumentation, the odds of success are pretty high. Just depends on how determined you are to learn. But it can definitely be done without digging up some old gravesite hoping to find discontinued official interneg film in a coffin.

DREW WILEY said:

I presume you mean a color interneg for sake of RA4 printing? It can be done in a very high quality manner using current films, either by contact or enlargement onto sheet film, but there's a steep learning curve to it. I recommend the enlargement method with 35mm originals. You need your colorhead set to around 500K using a good color temp meter. Use Portra 160 sheet film. The original should be between AN glass in the neg carrier, and preferably registered to an unsharp contrast-reducing masks (a big topic in its own right). The color neg sheet film should be in a sheet film holder firmly attached to the baseboard, and the lens set for an exposure time around 10 seconds (determined via trial and error, unless your really want this to become a complicated discussion).

Flashing can hypothetically be used to mitigate contrast gain in lieu of masking. I personally prefer the latter. But either way, it would take a much more extended discussion than I have time for now.

That will at least allow you to swing at the ball a few hundred times and hope to hit one. But with enough experience and some serious instrumentation, the odds of success are pretty high. Just depends on how determined you are to learn. But it can definitely be done without digging up some old gravesite hoping to find discontinued official interneg film in a coffin.

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Do you mean 5000K?

For the AN glass, I'm wondering if acid etched glass would be sufficient. I have plenty of glass lying around, and some etching cream.

I'll put the slide and negative in a contact frame, and expose it using the color head on my enlarger. Even though I'll lose some light through the frosted glass, I should be able to control exposure with time or aperture.

At this point my goal is to be able to give away a nice RA4 print of a slide portrait every now and then. I suppose if I take a great picture, it might increase my creative demands. I'll have to start taking some great pictures, first.

Thanks for spotting my typo, Alan. I corrected it.

focus - Etched glass if far too risky per pattern artifacts in film in a contact frame. It's even a bad idea for contact prints. I've experimented with all kinds of options. But for enlarger projection, for small originals, 35mm up to 6x7, a little secret for obtaining cheap AN glass of suitable size are leftover Gepe AN glass slide mounts. A number of them still seem to be around.

Acrylic has several problems. It's not dimensionally stable, and can bow or warp due to both heat and humidity changes. It's easily scratched. And worst of all, it's electrostatic and is a dust magnet. And in any kind of interneg or dupe or masking work, dust and lint is your mortal enemy. You need to think as if you were operating a true cleanroom. But small scraps of acrylic are cheap enough, and easy to size down, so you can always try and determine things for yourself. But from decades of sheer experience, I can state that true Anti-Newton glass is far better if you can acquire it.

Quality internegs from chromes is an imposing challenge for a beginner. It's a thousand times easier (and cheaper, once your realize all the gear you need) to just take color neg shots to begin with, and then print those RA4 style.

DREW WILEY said:

It's a thousand times easier (and cheaper, once your realize all the gear you need) to just take color neg shots to begin with, and then print those RA4 style.

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Or scan the 4x5 chromes and inkjet print. Or send out to any service provider producing chromogenic prints if it must be RA4.

koraks said:

Or scan the 4x5 chromes and inkjet print. Or send out to any service provider producing chromogenic prints if it must be RA4.

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Nobody is shooting film and running their own darkroom because they want it cheap and easy.

The post-scan laser prints via Lightjet, Lamdba, Chromira, then RA4, can do a good job mimicking real optical enlargements if a highly experienced operator is involved. Inkjets have a whole different look. Easy, maybe, but no necessarily cheaper than DIY in home darkroom. Yeah, making a precision interneg form a chrome can be an ordeal; but once you've got it, the actual enlargements are going to be quite economical unless something deluxe like Fujiflex is involved. And printing color neg fillm itself via RA4 is generally quite a bit cheaper than black and white FB prints the same size if you do it yourself. But run of the mill snapshots - why bother?

DREW WILEY said:

The post-scan laser prints via Lightjet, Lamdba, Chromira, then RA4, can do a good job mimicking real optical enlargements if a highly experienced operator is involved. Inkjets have a whole different look. Easy, maybe, but no necessarily cheaper than DIY in home darkroom. Yeah, making a precision interneg form a chrome can be an ordeal; but once you've got it, the actual enlargements are going to be quite economical unless something deluxe like Fujiflex is involved. And printing color neg fillm itself via RA4 is generally quite a bit cheaper than black and white FB prints the same size if you do it yourself. But run of the mill snapshots - why bother?

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Thirty years ago when I shot chromes and color negatives in medium format, I had about thirty of them printed in a pro shop in NYC in 16x20" using 4x5 internegatives (for the chromes). I think it cost me about $30 a picture back then. Then I had a local shop mat and mount them in 22x26" frames for around another $30-35 a picture. I still have the internegatives but don't know if they've faded or not. I've only got two still hung on the walls in our new place.

Since I don't have a darkroom, I develop all my new stuff outside but haven't printed yet and thinking about laser prints or another process. (I've continued to shoot MF 6x7 and now shoot LF 4x5 also in chromes and also BW negative)

Which processes would be best and why for chromes vs BW?

Drum scanning and laser printing would offer the most "photographic" look. But you're going to pay more. Some outfits allow you to do your own scanning and submit the files, but that requires a fair amount of setup, and won't equal results from their own scan. Take those old $30 - $35 apiece prices and multiply by ten, and quite a bit more for anything resembling a custom frame job.

But as per your old 4X5 internegs already on hand - all depends. How old? You could try one to see if they've significantly faded or not. And digital workflow would allow a least an amount of restorative hue re-satuation if needed. Older chrome originals themselves generally hold up better over time than older negs.

You can do inkjet prints yourself at home; so unless you want a big print, why not?