Interpositive size and film choice

Hi all,

I am about to start making enlarged negatives for contact printing. I am going to be doing so via interpositives, since I'm not inclined to deal with reversal chemistry (particularly homemade bleaches) right now.

I have seen two methods used. One is to contact print the original negative before enlarging from the positive; the other is to enlarge onto an initial interpositive.

My instinct is to enlarge the initial negative (which would usually be 35mm or 6x7) onto a 4x5 interpositive, then enlarge that again onto 8x10 (or whatever) for contact printing, rather to do one big enlargement. But is there a good reason to do it the other day?

Secondly, I have a choice of FP4+ or Rollei Ortho as the interpositive film; would I be better sticking with a traditional pictorial film, or using the high-contrast Ortho film, perhaps developed in a low-contrast developer like RLC? (Current instinct: Use FP4+ in ID-11 for interpos, and the Ortho film (which is the only one I have in 8x10) in either ID-11 or RLC as the final negative.)

I'm looking for a high-contrast negative that still contains reasonable midtone separation.

Thanks!

Have a look at my post here: (there was a url link here which no longer exists)

and within that you'll find a link to a thread at LFPF which is worth a close read. Bob Carnie is the man to pay attention to on this subject (also a member here)

If you enlarge your interpositive you can burn and dodge problem areas from your original negative. I've not doe it a lot recently but that was my regular approach. I always though I got a sharper finally internegative that way.

pdeeh said:

Have a look at my post here: (there was a url link here which no longer exists)

and within that you'll find a link to a thread at LFPF which is worth a close read. Bob Carnie is the man to pay attention to on this subject (also a member here)

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Interesting links, thanks for sharing and also for your effort on that post!

pdeeh said:

Have a look at my post here: (there was a url link here which no longer exists)

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Ha! Thanks! Those were exactly what I was looking for. I strongly suspect that this Rollei film will be very much like the old Agfa one. And I know that Bob really knows what he's talking about here too.
(Plus, it's an excellent week to follow your advice re getting annoyed at the state of the world! )

darkroommike said:

If you enlarge your interpositive you can burn and dodge problem areas from your original negative.

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Great point!

Your problem is that you are dealing with a very small original. So I would recommend making an enlarged 4x5 interpositive onto ordinary FP4. This interpositive should carry the full tonal scale of your original, but not have excessive contrast. You will need a good glass carrier, with glass on both sides, an enlarging lens suited for this kind of reproduction work, and ideally a vacuum sheet film holder, though an ordinary holder or simple removable double-faced tape method might be fine for learning purposes. Then the duplicate neg itself can be generated in a contact frame and developed for normal printing contrast.. Newton rings might be a problem, so you generally need to do contacts emulsion to emulsion. You can use an ordinary developer like D76 (ID-11), though I prefer HC-110. All this is quite easy in principle, though it takes a bit of practice to iron out the minor bugs. If you have a punch and pin-registered contact frame you can do all kinds of nice tricks, like attaching a sheet of frosted mylar with red dye
or pencil smudge on it to automatically dodge key areas, or even resort to unsharp film masking. It's a lot of fun.

I would recommend that you contact your inter pos on ortho/litho and then enlarge onto ortho/litho.

cliveh said:

I would recommend that you contact your inter pos on ortho/litho and then enlarge onto ortho/litho.

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I agree this other than I would contact onto ortho 25 and then enlarge onto FP4 .. contact internegatives are far sharper than enlarge internegs...

But Bob, why after contact printing onto ortho would you enlarge onto FP4. You have already lost the spectral sensitivity at the ortho stage. So why not enlarge onto ortho?

He's dealing with something small, Bob. Contact on that small scale likely means both grain gain and dust headaches. I certainly done that quite a bit,
but reach for ordinary TMX100 for the contact, then enlarge that onto FP4. Ortho film brings in some question marks because the specific products
available seem to change from time to time.

cliveh said:

But Bob, why after contact printing onto ortho would you enlarge onto FP4. You have already lost the spectral sensitivity at the ortho stage. So why not enlarge onto ortho?

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I am suspecting the OP has a negative which when contacting to ortho makes a flat positive, then enlarging the positive to fp4 you get an negative for printing.

I understand the dust aspects, but I made my living for a good 10 years from internegs and the best results always was from contact internegs, yes harder to control and make but IMHO much better results.

Most major labs worldwide would make projection internegs, the very best would make contact as there is a final difference... just sayin.

cliveh said:

But Bob, why after contact printing onto ortho would you enlarge onto FP4. You have already lost the spectral sensitivity at the ortho stage. So why not enlarge onto ortho?

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Sorry Clive I see your point yes you could enlarge onto ortho, I just used FP4 for this stage

I made duplicate negatives for years, colour and B&W, along with all of my other repro duties (internegs and dupes, mostly), when I worked for a large photo lab.

The usual request was for a volume of B&W prints from a colour negative; until Kodak started selling an RA-4 compatible B&W paper, we had to go the interpos & interneg route. AFAIR, Panalure paper wasn’t an option, either because it had been discontinued in rolls, or management didn’t want to stock rolls of a product that we didn’t use very often.

Our preferred method was to make an enlarged (sometimes reduced) interpositive from the original negative, originally on Super-XX Pan film, and after it was discontinued, on T-Max 100 film. The aim was to make a somewhat flat and dark positive; that way, it would contain all of the information that was in the original negative.

Next, we would make an internegative, by contact, on Kodak Professional Copy film, which was originally designed for copying B&W prints. It had a compound curve, with an upsweep on the highlight end; this was to maintain the contrast in the highlights of the original print being copied, or in the case of the internegative, to maintain the highlights from the interpositive. A surprisingly large number of photographers didn’t recognize that highlights, whether in a transparency, or a print/positive, have not only less density, but less contrast as the midtones.

This negative would be on its way to one of our roll-head printers, or one of the darkrooms equipped with a roll easel, for the quantity of prints desired.

Dust was a major problem. If you have a spot of dust on the original negative, it will make a light spot on the interpositive, and a dark spot on the internegative, which will give you a light spot on the final print, which can be hidden with spotting dyes. If, on the other hand, you have a spot of dust on the interpositive, it will make a light spot on the internegative, which will give you a dark spot on the final print, requiring etching or bleaching the spot to remove it.

I came up with a solution which worked rather well, and may be a consideration for you. I tried making an enlarged internegative in one step, by exposing the original negative onto Ilford XP-1 (or was it XP-2?) film, the C-41 processable B&W negative film. Forgive my vagueness on that point, as I haven’t made one of those internegatives in 18+ years!

Instead of processing it in C-41 chemistry, I processed it in E-6 chemistry, to produce a negative image, from a negative original, in one step. I found that the resulting image was very low in contrast, so my regular procedure was to push the film 4 stops, to get enough contrast to make a printable image. If you go this route, you will have to make some exposure tests, to be sure.

If you take the film to a lab, and ask for special processing, there may be an additional charge over whatever the lab’s regular fee is. You may also want to have a word with the manager about what you are doing, lest the film be run through the lab's C-41 line.

I made large Scala process negatives as well back in the day, been so long, today I make silver gelatin negatives directly from my lambda to many sizes in either positive or negative depending on what is needed, using Ilford Ortho Large Roll film .

Yeah dust. When I intend to do anything that involves registered film, I swab down every surface in my film room in advance. It's set up as a true
cleanroom with an industrial air cleaner, triple-filtered air compressor lines, enameled surfaces, etc. I also wear a 100% true cleanroom smock,
worth its weight in gold, but only about thirty bucks to buy, with no lint. I also use that same room for a couple of enlargers I like to use for black
and white printing in winter, because its a smaller space real easy to keep warm and cozy. And for routine uses like that I don't need to be nearly
as fussy. But fiber-based papers create lint, as does conventional clothing, so I clean everything prior to color printing or fussy film work. This is
just normal darkroom procedure as far as I'm concerned, and I kinda sneer at the crowd who says things can be cleaned up in Photoshop these days.
Well, I don't know which is worse - sitting on your butt for hours spotting negatives and prints, or sitting on your numb butt for hours at a computer station spotting in Photoshop. Working clean to begin with is by far the easiest option.