Top glass in negative carrier advantages vs disadvantages.

[Tin Can]

Many enlarger makers made glassless film carriers

Glennview has his own design

Tim Layton uses Calumet

I have 2 Calumet, bought from members here, when they went Digi

Very simple and very delicate in usage, just setting the frame and neg down too quickly on a flat surface can disturb

But once you know how

perfect

don't buy a bent one, Impossible to FIX

[Tin Can]

Here is Tim using one

https://www.timlaytonfineart.com/HeilandLED

[Michael R]

I think (like most things in the darkroom) if your negatives are staying flat/you are not losing any visible amount of print sharpness, you might as well continue as-is.

I’ll say a few things:

1. I think Bob is right regarding the dust argument against glass carriers. This is a non-issue. In fact glass might be better.

However…

2. Newton rings can sometimes be a difficult problem to solve. A tip I came up with a long time ago which might help people in a pinch, at least on the top surface of the negative) is to use a piece of unexposed, fixed out TXP (Tri-X 320) between the top glass and the negative. Because the base of TXP is designed for retouching, it has just enough “tooth” (texture) to usually prevent the formation of the interference pattern. So basically both the base and emulsion sides of the film should suppress Newton ring formation, and you don’t need to worry about whether or not the texture of ANR glass, Mylar etc. is fine enough. If you get Newton rings below the negative (sometimes can happen with films that have a shiny emulsion surface such as TMax and Acros) it’s a less trivial problem to solve.

So what if I manage to keep my negatives perfectly flat and aligned without using glass and without any risk of them popping? I get the benefits you speak of and the benefit of less risk of dust.

FYI, dust has always had far more impact on the quality of my prints than alignment and flatness issues. Not to mention Newton rings, which are a fact of life with films such as TMX in a climate that is often fairly humid.

I'm not saying a glassless approach is fundamentally better than one without glass. I am, however, advocating a real-world approach that takes into account local conditions, enlarger architecture and personal abilities/preferences. I don't see the need to dogmatically stick to one proven way only if other options work just as well in practice, or even better for some of us.

[Tin Can]

I am not arguing against glass

I am using an alternative

Same with lamps

DIY is LF

[Bernice Loui]

Glass and glass-less film carriers have their place depending what the print goals-needs are.

Glassless film carriers are easier to manage dust and general set up, but they can never keep the film flat as a proper glass film carrier. Glass film carriers have the ability to keep the film flat and stable over the time needed to make a GOOD print.

That said, roll film (35mm & 120) in the Durst 138 tends to bias towards glassless film carriers as the print quality is traded off for the number of prints that need to be made -vs- print quality. The glass carrier in the Durst 138 allows placing roll film sections making an enlarged contact print. Essentially, glassless film carriers trades off speed of set up for film stability in the enlarger.

If a serious print is made from 5x7 B&W film, it will go into the glass carrier. The Durst 138 film carrier has anti-newton glass on top with clear magnesium fluorite reflection aiding glass on the bottom (Durst item). Once set up, the film in the Durst film carrier will remain absolutely stable for hour after hour of printing. This does NOT happen with a glassless film carrier. The film in glass carrier will be held.. flat and stay flat. This will go a long ways to producing a nice sharp print given the enlarger is properly set up. Never had any issues with Newton rings using Durst anti-newton ring glass on top, Durst clear AR glass on the bottom. And no, stopping down the enlarging lens alone does not compensate for poor enlarger set-up/alignment and a enlarger that cannot remain stable and in alignment over the entire travel of the enlarger head to base board distance.

There is an unwavering preference to using the Durst 138 condenser head for all B&W prints as this condenser head properly set up with APO process lenses will produce sharp, snappy images diffusion enlargers cannot. This preference for the Durst 138 condenser head came after making piles of prints using both the Durst diffusion insert and other diffusion light sources in the Durst 138, then back to a properly set up Durst 138 condenser head.

This brings up the topic of both dust issues with glass -vs- glassless film carriers and the effects of differing light sources used in the enlarger.

As for dust, much like camera film holders, keep them and the working environment clean (Darkroom air filtration helps) goes a remarkable long ways to greatly reducing this problem.


Bernice

[Bernice Loui]

Durst 138 condenser head has a very effective IR suppressing system. It has a IR suppression glass filter, plus forced air cooling, plus a mirror to send the light path 90 degrees on to the condenser set which further suppresses IR/heat finally reaching the film carrier.

There is a filter slot in this light path allowing placing paper contrast filters in the light path instead of in front of the lens where these paper contrast filters can impact print image quality.



Bernice

Additionally, using a heat absorption glass near a hot light source is helpful, as it cuts a lot of the IR that causes the film to buckle/pop in any carrier... It will reduce Newton rings in glass carriers, as film has a more even tension under glasses, and in glassless carriers, film is not heating/drying and "popping" like before...

Steve K

[Drew Wiley]

Koraks - just depends on how demanding you are in terms of print sharpness. I have a friend who manages rather well with a glassless carrier for 6X6cm negs; but I can't personally imagine doing that for even 35mm film. Tried that long ago, and learned the hard. The larger film gets, the harder it is to keep flat. And the larger prints get, the more obvious the issue will be. Yes, the cooler the light source, the less the risk will be. But for someone like me, who needs very predictable precise results, often involving integrated pin-registered supplemental sheets of film, glassless would be anathema.

The idea that going glassless makes life easier with respect to dust - again, all depends. That won't protect you from little bits of dust settling on the film directly during exposure. If it's going to happen, I'd rather spend the extra work to meticulously clean the glass first, focus tightly on the emulsion grain, and have a bit of distance between that and any dust. And having cut my teeth of big Cibachromes, which could be a nightmare to retouch, I learned how to work very clean to begin with.

Scientifically, there is a correct answer to flatness and consistent precise focus, and it is glass on both sides. But in practical terms, everyone is obviously free to do what works best for them personally.

[Tin Can]

I will add, I process most film in Kodak Film Hangers with gentle gas burst partly to keep film flat

My film is very flat as it is hard to get rid of the slight air cushion when I do a dry flat on scanner glass scan

Stuffing film in cylinders, then wetting film with chems for a while does make a curved 'set' to film

[koraks]

Scientifically, there is a correct answer to flatness and consistent precise focus, and it is glass on both sides.

Scientifically, the best approach would be a glassless system that ensures perfect flatness and alignment in a dust-controlled environment (cleanroom). Glass in carriers is a compromise to ensure flatness and alignment. In practice, the compromise is evidently entirely satisfactory IF the glass is kept meticulously clean at all times. Personally I have always admired the tension system on the Durst Laborator negative carriers - a brilliant solution. I think Beseler had something similar, but with the unacceptable drawback that it very easily damaged the film.

[LabRat]

Another downside I have encountered while printing with glass carriers was when I was printing vintage sheet film negs (for a book project), and negs came from the (soggy) NE... Took a neg out of sleeve and examined on the light box first... Noticed it slightly started to warp, so left it out for awhile... Placed in glass carrier with condenser enlarger and examined it on easel, but noticed Newton rings were changing while I watched... Left light on for some time, and took out neg + carrier and reflected light off of it, but noticed reflected highlight had a very slight ripple in it... Put back into enlarger to "cook" it some more, and noticed a ring appearing around edges of neg...

I figure the neg had a high moisture content, and even with slight heating from light source started to cause uneven drying on neg with a almost imperceptible wave even between glass, and edges were drying differently as moisture could leave from there, but not as much from center of neg... Film would touch glass differently while sandwiched, and came out warped... Had to hang the rest of the negs from the job in the drying cabinet for a day unheated to slowly dry the films...

Had also had to print roll negs during very dry conditions (2% RH, where my fingers were like 10 spark plugs when I touched anything) and had Newton issues I never had before, and film warping and roll strips were rolling up like drinking straws (rehydrating it in moist environment solved issue quickly), but glass carriers in those extreme conditions were asking for trouble, and pull out glassless on those soggy or very dry nights...

Steve K