Anti-Newton Glass and Huge Enlargements

[Bob Carnie]

I use to use a graphite powder to eliminate newton rings on the Lisle camera.. basically needed to just put enough powder down on the glass surface. the negatives or positives
were then vacuumed down on them.
This worked incredibly well.

I never tried this for enlarging as I have never seen newton rings in an optical enlargement

 

[DREW WILEY]

To elaborate a bit more, Michael, I once had sampled of at least a dozen different kinds of AN glass for testing. Nowadays there are very few choices out there. The biggest issue would be with thin small negatives, like 120 roll film, where vintage genuine Durst or Omega AN glass seems preferable
to current choices. A simple trick in such instances is also to re-diffuse the incoming light directly atop the film itself using a sheet of 5-mil translucent
(frosted) mylar (not frosted acetate, which will show texture). There are just all kinds of tricks out there that I've learned over the years if someone
is serious about double AN technique. But you can't necessarily take just any film, any enlarging lens, and any light source and expect this to work
predictably. I got fed up with fluid mounting way back when I spent hours on end working with immersion oil under a microscope, then needing to
clean it off every time. Guess I wouldn't enjoy drum scanning either, for the same reason.

 

[DREW WILEY]

Here I go again - back to Bob. Graphite goes all kinds of places you don't want it. And heaven help you if it gets inside a lens. I wouldn't use it anywhere near a camera or enlarger, not even a darkroom door lock. Typical anti-newton "offset" powder, as well as the primary ingredient in modern anti-newton sprays for scanning is a very finely sifted corn starch. You spray it into the air below a gentle fume hood, then swipe the negative through the mist. Never spray directly on the neg (speaking in general, Bob - I realize you probably know all this stuff better than I do). The old guys would just use a rubber puffer bulb instead, with dry corn starch powder. I keep some of the spray cans on hand, but haven't used them in a long time. Two problems. Unlike a correct AN glass, antinewton powder will inevitably show up on serious enlargements. And it still needs to be thoroughly cleaned off the neg afterwards. The aerosol version has some unhealthy things in the propellant. The primitive powder itself will attract booklice to your equipment, and tend attract them to things like bellows glue, or just become a nuisance like graphite. Offset presses were 1:1, not enlarging devices, so they didn't have quite the same concern.

 

[Bob Carnie]

Yes the technique as I remember was to shoot the powder into the air and bring the lexan loaded with images through it, once vacumned down you would look at each image for Newton Rings and of Course the powder.

Blind Pig - Don I prefer using his real name here an APUG would also have used this for his Lisle Camera and probably has some serious ways of avoiding the dreaded ring.

Drew did you know in Australia the ring was backwards?

 

[Bob Carnie]

I also think Humidity has a big effect , but may be wrong. The effect once described to me if memory serves me correct was due to a refraction of light.. I have not seen them for many years so they have not been an issue for me but this thread brings back agonizing research.

I have a wet mounting station on my scanner and some clients refuse to have any of the mount fluid on their negatives... can't say I really blame them.
I remember getting transparencies that have gone to press and were fluid mounted and lots of issues.

Newton rings have luckily only been a relatively rare (intermittent) issue for me, and luckily never below the negative, even with TMX. Like you say, there are little tricks that seem to work (I've used TXP above the negative for example).

But it is sometimes hard to tell if something is working or not because the problem is intermittent in the first place. This has been the case for me, for example, when experimenting with various coated optical glasses. A few years ago I went on this dumb kick trying all sorts of exotic ideas with coated optical glasses, and also a bunch of fancy framing glasses when I decided to make a registration carrier for 35mm. My reasoning was that you need reflection to get interference patterns like Newton rings (maybe Jason could comment). These things seem to work, but it could just be luck because like I said, I've only occasionally seen Newton rings to begin with.

On the digital side, my understanding is that wet mounting also reduces some of the graininess issues associated with scanning. I might be wrong.

 

[DREW WILEY]

What I remember from my serious geophysics education is how a dog will walk around a woven throw rug counterclockwise in the northern hemisphere before laying down, but clockwise in the southern hemisphere. Right on the equator itself, the dog will simply lay down because it
can't decide. That's how ancient Polynesian explorers found their way over the Pacific Ocean - they always had a dog and throw rug on the boat!

 

[DREW WILEY]

... Yes (back to sanity)... humidity is a significant factor. Since it is foggy more days of the year than not around here, newton rings are a constant
problem for me. But some of these newer thin emulsion films like TMX, Delta, and ACROS can be a real headache even on the emulsion side, and
of course, most color films. The new Portra and Ektar sheet films are wonderful to work with because the surface treatment they add to facilitate
scanning also doubles as to minimize rings. Same goes for the deliberate texture on Arista's current Ortho Litho films. And most of us know about
the retouch "tooth" on classic old black and white films. Problem is, the best current film for certain masking and color separation purposes happens to
be a slick one - TMX.

 

[Hilo]

Last year I photographed an anti newton treated condenser of the Leitz Valoy II and the clear condenser of the same enlarger.

I was quite amazed by the difference.

Photo attached

 

[Bob Carnie]

Last year I photographed an anti newton treated condenser of the Leitz Valoy II and the clear condenser of the same enlarger.

I was quite amazed by the difference.

Photo attached

I have never seen a AN condenser before - the rings pop out on the clear one.

 

[DREW WILEY]

Fascinating. So Leitz figured it out, that is, the relation between incidence and diffusion by controlling proximity of the latter. Really, I shouldn't be surprised, since by far the best AN glass came from Belgium (no longer made), and I do have some very unusual pieces of Zeiss optical flats specially coated for AN control, far superior to any of these recent attempts to control rings with optical coatings. Got one case of it, and never have been able to find any since. Probably surplus from some custom industrial run. But back to Leitz, I'd imagine they pioneered this concept in relation to
microscope condensers, since that was a field they excelled at.

 

[Hilo]

I had a Focomat Ic years ago (bought new ~1960) that I'd swear had the lower surface of the condenser lens treated for AN rings (which I never experienced), but a guy from Europe said he was certain that Leitz never made such an item and that they did offer an AN attachment for that condenser. I'm positive I had no such attachment.

Leitz only made this AN condenser for the later models of the Valoy II, which were dark grey and light grey. The first black Valoy II had the clear condenser. If you are sure your enlarger had such a frosted condenser you either did not realise the Focomat 1c had the AN glass attached (many people don't) or you had the Valoy II.

The an condenser is a beautiful system. However, when you damaged that lower side of the condenser you'd have to order the entire condenser. That was the reason why Leitz did not make the same for the 1c and instead made the an glass that could just be attached. The Ic was an enlarger used in many newspaper darkrooms, not exactly the place where people were careful.

Back to the original question: I never realised AN glass came in different qualities, or 'structures'. If that structure is on the outside of the glass (which I guess it would be) then yes, it could show in the print. It would be in focus as it is pressing on the negative.

 

[Europan]

Anti-Newton ring glasses are etched. Some a little deeper than others, that’s the only difference.

My solution for the problem or precaution against the fear of seeing Newton rings on screen would be to make replaceable positives and cement them in under smooth glass. You have Canada balsam and a number of synthetic lacquers for that purpose. When you have reversal originals you can have difficulties finding reversal duplicating film depending on the format. From 4" by 5" on you can reproduce a slide with the same film, cut to fit. Gigabit film is fantastic as internegative with 24 × 36 black-and-white images.

Super Slides, 1½" by 1½" image surface, is a nice format. From my former life as theatre projectionist I know the so-called ideal format which I love. I think there’s always a way. Where there’s a villa, there’s a way.

 

[DREW WILEY]

No. That is not the only difference. You are completely wrong on that one.

 

[Bob Carnie]

Gigabit film is fantastic as internegative with 24 × 36 black-and-white images.

I am not familiar with Gigabit film - could you describe it please

 

[RobC]

http://www.gigabitfilm.de/html/english/menu.htm

http://spur-photo.com/some-information-in-english/

I think SPUR is Gigabit

 

[Hilo]

I have never seen a AN condenser before - the rings pop out on the clear one.

To be honest: I don't think those rings in my photos have anything to do with Newton rings. They are just a result of the rounded glass on the rear side of the condenser.

 

[Hilo]

Anti-Newton ring glasses are etched. Some a little deeper than others, that’s the only difference.

My solution for the problem or precaution against the fear of seeing Newton rings on screen would be to make replaceable positives and cement them in under smooth glass. You have Canada balsam and a number of synthetic lacquers for that purpose. When you have reversal originals you can have difficulties finding reversal duplicating film depending on the format. From 4" by 5" on you can reproduce a slide with the same film, cut to fit. Gigabit film is fantastic as internegative with 24 × 36 black-and-white images.

Super Slides, 1½" by 1½" image surface, is a nice format. From my former life as theatre projectionist I know the so-called ideal format which I love. I think there’s always a way. Where there’s a villa, there’s a way.

Sorry, but you lost me. I do not understand anything of what you talk about. However, I like a lot: the "precaution against the fear of seeing Newton rings". I am all for non linear ways of understanding things and love the Hitchcockian implications of your line !! There's a certain darkness to your darkroom ideas, great !!

 

[DREW WILEY]

Well, at least one idea has been floated even more convoluted and messy than fluid mounting.

 

[Ai Print]

I do know of a few people who have been able to make ANR glass under the negative (for example with TMX) work. I haven't ever tried that. Luckily I haven't needed to.

I could not get it to work and it was driving me totally nuts, so I crafted custom neg carriers out of my AN glass carriers...I managed to amass 4 of them in LPL 4x5 for not a lot of money.

What I did was AN glass on top and then no glass on the bottom. Instead I crafted custom plastic frames that sandwiched the film at the rebate with just enough wiggle room to be full frame. I got the idea from the LPL glass on top only carrier for 35mm. I did this for 4x5, 6x12 and 6x6 negs which besides 35mm, are all I shoot.

The setup seems to hold the film flat fine, newton rings are a thing of the past and I can print using the lens wide open if for some reason I wanted that because the film is flat. Two less surfaces to check for dust as well.

 

[Europan]

There's a certain darkness to your darkroom ideas, great !!

Flattering me

Hope to bring it back on track, another trial: You don’t want any visible structure on screen from AN glass. The etched surface, above all the one in contact with the image side of the film piece

You don’t want no Newton rings, either. In order to avoid them I suggest to use conventional glass but do away with any air between film and glass by cementing the slide. Optically, the optimum would be immersion like with microscopy. The back lens of the optical system is in contact with a fluid that bridges it to the object. That would be a hell of slide projector. So far, I have never heard of or seen an immersion slide projector. Advantage: large aperture of f/0.8 feasible, even more.

 

[Ian Grant]

For optical testing, I've used index matching fluid (a light oil) to eliminate Newton Rings between two surfaces. Is there an analogous approach for this application?

Yes it's used with drum scanning today but was first advocated in back in the 1920's in a BJP article in 1926 to get the highest quality from 35mm negatives. Ctein also wet mounts his negatives for printing.

Ian

 

[RobC]

I thought he sold off his remaining dye transfer print materials, or tried to, and has converted to inkjet printing.

 

[Ian Grant]

He may have done but the relevant part was the wet mounting negatives for printing.

Ian

 

[BMbikerider]

I use a LPL7700 enlarger and have both the normal multi-format negative carrier fitted with the standard AN top glass This glass is 2mm thick. I also use a 35mm glass-less carrier which I have modified with a single top glass similar to a Leica V35 Enlarger which has an AN top glass only.

This AN top glass, was originally a AN glass from a GePe 6x45 slide mount which is only .8mm thick and to be honest I cannot see the difference printing from either carriers, except when using the modified 35mm carrier with the single glass, there is always less dust. I am limited to a maximum size of 12 x 16 prints, but sometimes I enlarge to a greater size, but use only a centre portion of the image. Never have I seen any suggestion that the AN glass on either carriers shown on the final picture. It seems to be largely an urban myth.

 

[Old-N-Feeble]

So it seems the ultimate is wet mounting with regular glass. That must be an awful mess with 4x5 but I'll be doing so few very large prints I suppose it might be worth the effort.