ULF film flatness idea

[Fr. Mark]

About a week ago I took the "heart" out of a graphic arts camera at a print shop dating back to 1946 that is going out of business---the camera is, I think 1970's or 80's vintage, but I really don't know that for sure. I got a 20x24 bellows that's ~4 feet or ~1.2 meters long and the 45 cm f11 red dot altar lens. If I'd had a crew and a truck and a place to store it, I'd have gladly taken the whole camera. Looking darkroom side, there is a flip up and out of the way ground glass (plexiglas actually) and a flip up and into place vacuum requiring film holder that weighed enough to require a spring assist much stouter than a common household oven door.

Some day I'd like to make this into a version of a field camera and if I made my own dry plates on plexiglas flatness wouldn't be an issue---though I'm not sure how UV transmits through plexiglas (perspex for the Brits and Aussies), for alt process printing I like. But, if I used film, keeping a piece of film that big flat from the edges has got to be problematic, right?

Has anyone made holders that use vacuum assist using a small, battery-powered vacuum, through a hose to eliminate vibration, as a way to keep film flat in ULF holders? I don't think it would have to make the holders that much more enormous or heavy, but I'm often wrong about "obvious" things when it comes to engineering. I guess you'd have to be sure to clip the corners of your ground glass so you didn't implode the whole camera.

[Vaughn]

Someone in China is making them...

\https://www.largeformatphotography.info/forum/showthread.php?160164-Wooden-Vacuum-double-sheet-film-holders

Whoops -- you have seen the post!

[Monty McCutchen]

About a week ago I took the "heart" out of a graphic arts camera at a print shop dating back to 1946 that is going out of business---the camera is, I think 1970's or 80's vintage, but I really don't know that for sure. I got a 20x24 bellows that's ~4 feet or ~1.2 meters long and the 45 cm f11 red dot altar lens. If I'd had a crew and a truck and a place to store it, I'd have gladly taken the whole camera. Looking darkroom side, there is a flip up and out of the way ground glass (plexiglas actually) and a flip up and into place vacuum requiring film holder that weighed enough to require a spring assist much stouter than a common household oven door.

Some day I'd like to make this into a version of a field camera and if I made my own dry plates on plexiglas flatness wouldn't be an issue---though I'm not sure how UV transmits through plexiglas (perspex for the Brits and Aussies), for alt process printing I like. But, if I used film, keeping a piece of film that big flat from the edges has got to be problematic, right?

Has anyone made holders that use vacuum assist using a small, battery-powered vacuum, through a hose to eliminate vibration, as a way to keep film flat in ULF holders? I don't think it would have to make the holders that much more enormous or heavy, but I'm often wrong about "obvious" things when it comes to engineering. I guess you'd have to be sure to clip the corners of your ground glass so you didn't implode the whole camera.


I've never pursued that with my 20 x 24 work. I just load them up and make the photograph. I've never noticed an issue with that approach. A more discerning eye may be able to prove a counter point to that with my photographs but overall I don't think its worth the time or money to worry about film flatness--but again that is for MY photography. Your mileage may of course vary depending on what you are wanting to achieve. Overall I don't worry about overcoming such things as dust, film flatness. I have too much on my hands overcoming me.

[Tin Can]

Good to know Monty, I am only going to 14X17" vertical with Medical holders and Ektascan.

The simpler the better.

Thank you!


I've never pursued that with my 20 x 24 work. I just load them up and make the photograph. I've never noticed an issue with that approach. A more discerning eye may be able to prove a counter point to that with my photographs but overall I don't think its worth the time or money to worry about film flatness--but again that is for MY photography. Your mileage may of course vary depending on what you are wanting to achieve. Overall I don't worry about overcoming such things as dust, film flatness. I have too much on my hands overcoming me.

[Vaughn]

1) Low tack adhesive spray (after removing the rails that normally keep the film in place)

or

2) Always point the camera up.

[Fr. Mark]

Vaughn,

The low tack adhesive spray makes a lot more sense to me than always pointing the camera straight up!

I have this tendency to go to the most complicated process I guess.

[Vaughn]

Nah, just a little back tilt will do... ;)

[Drew Wiley]

Vaughn - spray adhesive is damn dangerous stuff! Should never be used outside a spray booth and is highly flammable. A whole generation of the pro picture framing trade lost many members due to premature death, before word got around just how nasty that stuff is. I've already posted many times on how to make adhesive filmholders using the proper 3M sheet products. It's also easy to make a vacuum holder; and any little cordless vacuum does fine. Those silly little vacs even work for my 400 lb 30x40 inch vac easel in the lab, though I prefer a variable power small plug-in vac because one can only use rechargeable batteries so many times until they need replacement.
Film sag is a serious issue even in 8x10 photography if one enlarges them much. I can't imagine doing ULF without some provision for improved flatness. And there's nothing quite as unnerving as seeing an ocean horizon line or allegedly vertical building squiggly-edged due to film flatness issues.

[Tin Can]

I suggest empirical testing with actual format and film you use, put into the holder, put holder in various real life shooting positions/angles, pull the DS and observe for week or more under your shooting conditions

document with iPhone

and post the dern evidence on this forum

few will do that

everything else is babble

[Drew Wiley]

That "dern evidence" has been well known for generations. It's been an obvious problem ever since flat glass or metal plates were no longer used. Later a little tab of ATG tape was put behind the middle of the film - not the best idea but it halfway worked. Vac holders in one fashion or another are nothing new. And if you want serious evidence, find me a graphics copy camera anywhere that didn't require a vac easel - the real ULF machines!
The bigger the film, the more the overall problem. Sinar offered adhesive holders in 5x7 and 8x10; and I think that right around 5x7 it starts becoming a noticeable issue with moderate enlargements. For technical or scientific projects, even 4x5 should be controlled. For ordinary contact printing applications, all depends. ULF film is generally contact printed, but mere perceived sharpness is not all that is in play here. I once saw a 16X20 AA print with a distinct sag in the ocean horizon.

[Fr. Mark]

The camera that the bellows came out of was a graphic arts camera with a v. heavy vacuum back. I'd do almost anything to avoid having to run a noisy vacuum pump---I might could live with a quite one and it wouldn't solve the use of "miniature" film in giant film holders which might be nice for tests. I suspect that if I build this camera I'm going to have to make my own film to afford to be able to use it and I'm originally trained as a chemist and have wanted to try this for years. If so, I might just put the "film" (emulsion) on plexiglas, which is not as rigid as glass might be better, if only because it wouldn't have waves, just a single dip, or at least I think so.

Do these low tack adhesives remain low tack for a long time? Is it hard to get the residue off? When I first started this LF game I taped bits of 35 mm film into 4x5 holders just to have something to try and the electrical tape was a poor choice---it lifted the paint off the septa of the holders, it left gobs of adhesive behind. Yuck.

I believe Drew is right that for crucial scientific applications (astronomy surveys) the negative of choice was something a lot like tech pan on glass since you couldn't know for sure where your camera would point and sag would mess up measurements. I'm pretty sure that the original holders for glass plates did use 8x10 pieces of glass and when those were retrofitted or additionally fitted with metal inserts for thinner flexible film the film size had to be reduced slightly to fit in the metal holders and ever since 8x10 film hasn't been actually quite 8x10. Somewhere I have some non-modern standard ?Kodak? 8x10 holders like that. I'm not sure where you get glass or plexiglas thin enough but I'd have to dig a while to find them to measure things, sorry.

I don't know what the toxicity would be from spray adhesives. Many things, potentially. I've used high strength spray adhesive for affixing formica to telescope bearing surfaces but I always spray it in the driveway well away from the cars. These days the propellant is likely butane (or similar) which is what Bic lighters run on. Safe from explosion propellants like freon being disallowed. More than a few wet plate practitioners died in fires, ether and ethanol and nitrocellulose all being either motor fuels, or components of smokeless gunpowder, this in an era when a darkroom light was probably red-glassed kerosene lantern. I don't want any of us to suffer that kind of fate or any toxicity. I'd like to try some wet plate and dags for bragging rights, but I'm not really in a hurry and don't want to make it an ongoing thing. Gelatin emulsions offer a lot of advantages.

[Fr. Mark]

Another crazy question then, what about roll film for ULF/LF? That would require a vacuum back as adhesives would stop the film motion. The military used LF or ULF film rolls for aerial reconnaissance. I doubt that film is still available to the public if it ever was. So, first I'd have to figure out how to make film. To get 12 exposures of 20" squares would require 20 feet of film (or more with a smidgen of leader and space between frames). I don't foresee having a space that big in which to make the film... I wonder if something like that could be made light enough to compete with film holders for weight. With the right darkroom set up the individual frames could either be cut apart before or after processing. Blackout cloth like for curtains could be used for backing, film registration markings would have to be drawn/stenciled on the back.

[Vaughn]

The Polaroid 20x24 cameras used rolls. The cameras are still out there somewhere.

PS...they brought one out special to Sante Fe, NM (outside), but the change in humidity made it unusable due to light leaks.

[Tin Can]

Many roll film cameras use a spring loaded pressure plate

Some used vacuum

Rolls of paper emulsion ready made are still sold

Thought experimentation is not free

Time eats life

[Fr. Mark]

Many roll film cameras use a spring loaded pressure plate

Some used vacuum

Rolls of paper emulsion ready made are still sold

Thought experimentation is not free

Time eats life

I'd seen that Ilford makes rolls of printing paper still. That won't work for UV contact printing.

Life does get consumed with darting about chasing lots of ideas, but sometimes that's exactly what makes life worthwhile, no? The way the rest of the photographic world thinks, all of us LF enthusiasts are nuts.

[Monty McCutchen]

That "dern evidence" has been well known for generations. It's been an obvious problem ever since flat glass or metal plates were no longer used. Later a little tab of ATG tape was put behind the middle of the film - not the best idea but it halfway worked. Vac holders in one fashion or another are nothing new. And if you want serious evidence, find me a graphics copy camera anywhere that didn't require a vac easel - the real ULF machines!
The bigger the film, the more the overall problem. Sinar offered adhesive holders in 5x7 and 8x10; and I think that right around 5x7 it starts becoming a noticeable issue with moderate enlargements. For technical or scientific projects, even 4x5 should be controlled. For ordinary contact printing applications, all depends. ULF film is generally contact printed, but mere perceived sharpness is not all that is in play here. I once saw a 16X20 AA print with a distinct sag in the ocean horizon.

Ansel seemed to have survived the catastrophe just fine I would say. As I said earlier we all have to make decisions for our photography for ourselves. For my photography and the way I contact print on art paper with hand coated Pt/Pd salts I'm much more concerned with creating a photograph that is compositionally sound, creates atmosphere and mood, and conveys something beyond technical proficiency. The trick to your point Drew as I see it anyway is the technical proficiency can't detract from the above goals. If a lack of film flatness does just that--detract then it should be addressed. I suppose that is all in the eye of the beholder of course but as of now I've never had an issue with my 10 x 12's, 7 x 17's or my 20 x 24's. Again that is for me and the goals I have set for myself. Each to their own as it should be I suppose when you consider the overwhelming majority of us on this forum do this much more for ourselves than for any true impact or notoriety we might enjoy through the pursuit. As such we have to please our own sense of balance for technical proficiency and artistic expression.

[Jim Noel]

Other than the times i have aimed my 8x10 almost straight down, I have never had a problem with 8x10, 5x12 or 7x17. Why? I don't know, probably just dumb luck.

[Vaughn]

I have had issues with 8x10 many times...long exposures under the redwoods...30 secs to several minutes long. It has been mostly the film not sitting square in the holder, then falling square during the exposure. Usually one corner will be relatively sharp, the rest getting worse towards the opposite corner (which moved the most). Cured by a gentle thump on the bottom on the holder with my hand before loading into the camera. And sometimes a negative will just pop in the holder for reasons of its own. Going from warm/dry to cold/moist once the darkslide is removed, perhaps.

My 11x14 holders tend to have much heftier rails for the film to be held by than 8x10...probably helps some.

[Drew Wiley]

Film thickness varies somewhat overall. Film base stiffness is another factor. The worst scenario for me was when color sheet films were nearly all on floppy triacetate base for over well a decade. That wasn't dimensionally stable either, causing real headaches with mask registration. But that was also right around the time I shifted from 4x5 to mainly 8x10 shooting for quite awhile, and soon began using adhesive holders in relation to color film. All my black and white films had more stable polyester base, however, just like most do today, and I don't print b&w larger than 20X24 anyway - less than 3X enlargement from 8x10. With color I'd frequently go up to 30X430 inch prints, so had to be more nitpicky in that case with flatness issues in the holder. Once in awhile in cold damp weather I'd adopt an adhesive holder for b&w 8x10 film due to the potential risk of what Vaughn just described, though temp related popping has actually happened to me only once.