Negative duping/copy lenses recommendation

[FL at CC]

Hi everyone - I'm seeking some guidance for recommended lenses for making enlarged internegatives from 6x6/6x7 to 4x5 and conversely 4x5 to 8x10.

I'm using some of my Bergger Print Film to enlarge the interpositive to make the final neg, though easily as expected my Apo-Rodagon 80mm doesn't seem to have the brute performance needed.

Any suggestions welcome!! Have a wonderful day!

 

[Don_ih]

as expected my Apo-Rodagon 80mm doesn't seem to have the brute performance needed

Why wouldn't it? That lens should be good enough for it. Are you using it in the enlarger to project onto the 4x5 film?

 

[FL at CC]

Yes, I'm projecting the 6x6 sized interpos onto the 4x5 print film. Could it be that my Rodagon may not be optimized for this kind of thing?

 

[Don_ih]

Is the 4x5 film on a matte black surface? It can't be on a white or yellow easel.

The Rodagon is optimized for projecting a flat negative onto a flat surface.

 

[FL at CC]

Is the 4x5 film on a matte black surface? It can't be on a white or yellow easel.

The Rodagon is optimized for projecting a flat negative onto a flat surface.

Yes, I have some very opaque matt board directly beneath the 4x5 film, not directly on the white painted surface of the easel. My thinking is if the lens doesn't quite perform quote as well at the 1:1 / 1:2 mags. Thus why I've reached out.

 

[Don_ih]

You could try a 150 or so lens to take advantage of the greater area of centre sharpness. Pretty much any good enlarging lens greater than 80 should be able to do what you want.

You could put the sheet film in a 4x5 holder with the slide removed. That would keep the film flat. Mat board may not be that flat.

Maybe we should try to summon @DREW WILEY

 

[FL at CC]

A very good suggestion for the 150, thanks Don!

 

[Don_ih]

I also wouldn't expect to easily get the greatest results from the copy film you're using. It seems to be naturally very high contrast and a difficult to tame.
Also, there will be loss of image quality with any copying procedure.

 

[Terrence Brennan]

Hi everyone - I'm seeking some guidance for recommended lenses for making enlarged internegatives from 6x6/6x7 to 4x5 and conversely 4x5 to 8x10.

I'm using some of my Bergger Print Film to enlarge the interpositive to make the final neg, though easily as expected my Apo-Rodagon 80mm doesn't seem to have the brute performance needed.

Any suggestions welcome!! Have a wonderful day!

What is the purpose of the enlarged internegatives? Are they to make very large prints?

 

[xkaes]

It's easy enough to look up the specs on that lens. If it's a copy/process/macro lens it will work fine.

 

[ic-racer]

Longer lens won't be any advantage over a reputable 6-element 80mm lens used for 2x enlargements.

Either you have a lens that has been tampered or something is wrong with your setup; movement, focus, alignment, etc.

 

[Oren Grad]

The Apo-Rodagon-D series is designed / optimized for duplication and internegative work, with the three lenses covering formats up to 4x5. They're expensive new but with patience can be found on eBay at a fraction of the price for new - I assembled a complete set that way.

 

[Lachlan Young]

something is wrong with your setup; movement, focus, alignment, etc.

Or the contact between original neg and interpos wasn't tight enough. I don't think it's the lens at all, but probably a sequence of small losses across an insufficiently capable system.

It is shockingly easy to make decent copy negs with basically competent kit, and incessantly amazing to me that people either dramatically screw it up or insist that you need pieces of scrap naval hardware bolted on to bedrock to do it properly...

 

[Mick Fagan]

Is your enlarger perfectly aligned with your baseboard?

Are you using glass holders in the negative stage?

The standard we used for 4x5" internegatives, was to have a 4x5" film holder permanently attached to an easel, with the film holder being parallel to the easel.

We also had a fixed airgun from a filtered air compressor with a knee operated lever, which turned a wide spray of clean air over the negative just prior to exposure; to a large extent, this eliminated dust on the film being exposed.

For 8x10" negatives we also had a film holder fixed to an easel, but once we started using a vacuum easel, we never went back to the film holders.

In my home darkroom, I used film holders for 4x5" negatives.

Later on I made a home made vacuum easel using a cheap Godfrey's vacuum cleaner sitting outside the darkroom; worked very well. This was mainly used to successfully expose Kodak 10x8" Print Film for colour transparencies.

1.5mm holes drilled into a piece of Laminex was my home made vacuum easel. I tried 1mm but it didn't have enough suck, so I enlarged the holes to 1.5mm and it worked.

 

[jeffreyg]

I’m not sure what you intend to do with the enlarged negative. I have enlarged negatives to make pt/pd prints If that happens to be your end result (an alternative process contact print) and you want to stick to analog I suggest saving yourself extra steps and use x-ray duplicating film. I have made many enlarged negatives for pt/pd prints It’s a reversal film handled like making a positive print but ending up with a high quality negative. Since it’s a reversal film you do the opposite with exposure more gives a lighter neg - for a darker print and visa versa. It is also slow so a little trial and error is involved to develop your technique. Exposing with the enlarger lens wide open helps. Using the black matte paper under the film in the easel is also a good idea.

 

[DREW WILEY]

I need to make an enlarged interpositive today. A 6X9 color neg in AN glass Durst carrier, 240/9 Apo Nikkor process lens, pin registered 8x10 vacuum board, Tmax film. Next step - the actual b&w printing neg itself will be done in a pin-registered 8X10 contact frame, emulsion to emulsion.

Lachlan - you should move here. Yes, you do need a setup built like a battleship, bolted down every direction. An infamous earthquake fault is just up the street from me. At least my building is underlain by granite bedrock, so the shock waves pass through very fast with minimal effect. But most of the area is built over poorly consolidated Miocene mudstone, or even artificial fill, which shakes like crazy - basically jello.