Appropriate chemicals for wet mounting negatives in carrier?

[ChrisBCS]

This may be a bit rambling. The 6x7 negative carrier that came with my enlarger permits too much negative sagging. My personal requirements (that would allow me to sleep at night) are edge to edge razor sharpness. Right now I'm not getting even acceptable corner sharpness after grain focusing the center.

The Fujimoto G70 negative carrier is extremely simple and could be replicated in physical practice by a sandwich of 2 x 2mm glass plates. Now, of course, the fear is the dreaded Newton Ring. It seems to me barring spending the money on ANR glass, as a opposed to the pittance of sheet glass cost, fluid mounting is the most robust, repeatable solution (hah).

Now the chemist in me reads APUG, etc. about mounting fluids and scanning fluids and powders galore. My skepticism wonders if there isn't a simple, readily available fluid that can be placed on the film base before sandwiching. Hexane comes to mind, as it would be slow to evaporate and have a thin, low viscosity coat.

Any thoughts? what are your experiences?

 

[MattKing]

You don't want to have to deal with cleaning wet mounted negatives.
Millions of photographers have successfully used glass carriers. Your spotting brush is your friend .
By the way, a single, top ANR plate can make a real difference.

 

[ChrisBCS]

Thanks @MattKing . Am I over-anticipating the problem as a result of my inexperience? I'm guessing many of our "favorites" were printed with plain old glass.

Is focal point a good source of ANR glass?

 

[MattKing]

I do almost all of my prints with glass-less carriers, but if I were to print really large, I'd either use my glass carriers, or visit my friends who have high end Durst enlargers and (now that they have moved) a really nice, large darkroom.
I've never had to buy ANR glass, but I understand Focal Point are a good source.

 

[Ian Grant]

My preference has always been glass in the bottom of a carrier and a metal mask in the top, that stops negatives sagging but cuts the effects of dust dramatically.

Ctein used to advocate wet mounting negatives, you could use the same fluid as used for scanning. The technique goes back to 1925/6 when it was first advocated for making the highest quality prints from miniature film negatives, at the time miniature meant 120 RF as well as 35mm.

Ian

 

[AgX]

The fluid must have the same refreactive index as the emulsion or as the base/rear-layer.
It must not attack base or any layer. It should not diffuse into the emulsion.

 

[Neal]

Dear ChrisBCS,

Focal Point is a great source for negative carrier glass sets. I bought a set in the last year for my Omega D5 carrier and it fit perfectly.

While I've used Edwal No-Scratch quite a bit on old negatives, I've only used it once with a glass carrier. There were no issues.

Good luck,

Neal Wydra

 

[Kino]

The fluid must have the same refreactive index as the emulsion or as the base/rear-layer.
It must not attack base or any layer. It should not diffuse into the emulsion.

Motion Picture wetgate printing/scanning uses Perc (perchloroethylene) or the low toxicity SES3 fluid from Kodika. Perc is outlawed in many countries, both are a huge pain to use; the first toxic to the liver, the second slightly flammable, both require extensive and expensive pressurized delivery, recovery and recycling technology.

The Aztek/Kami fluid for Epson film scanners is effective, but labor intensive and messy.
http://www.aztek.com/consumables.html

Old timers used "nose-grease". http://www.largeformatphotography.info/forum/showthread.php?15124-Nose-Grease-on-Negatives

Good luck.

 

[AgX]

Pressurized delivery? PER for instance is a fluid at room temperature. And such is needed for wet-gate copying anyway.

 

[Kino]

Pressurized delivery? PER for instance is a fluid at room temperature. And such is needed for wet-gate copying anyway.

For motion picture work, such as in an optical printer, it is required; the film slips between gaskets in the wet gate assembly as it is printed, thus drawing off a minute portion of the perc. The perc is injected under pressure at the top of the printing aperture and and evacuated at the bottom in a delicately balanced manner. The fluid is heavily filtered and special bubble traps are employed to avoid passing bubbles through to imprint artifacts upon the new element. Printers can also use large aquariums of perc that immerse the entire rotary contact printing mechanism, but they also inject the perc just prior to the printing aperture, under pressure and the same elaborate bubble traps, filters, evacuation air ducts and filtration are required. The major difference is our highly modified optical printers run at a relatively slow speed of about 1 to 2 frames per second and the rotary contact printers can run at speeds up to 120 feet per minute.

In theory, you could make a printing tray to hold a small amount of perc in an enlarger, but unless you had an elaborate ventilation system, it would run out out of the room in short order.

 

[adelorenzo]

I use a glass carrier for all of my printing. It was expensive but definitely worth it IMHO. Never tried wet mounting in the enlarger.

A few other questions to consider:

Have you checked alignment of your enlarger? Are you using a good quality lens of the right focal length? Stopping down to optimal aperture?

 

[AgX]

Kino, I see now what you meant, but I understood your wording "Pressurized Delivery" as pressurized transport to the lab.

 

[Kino]

Kino, I see now what you meant, but I understood your wording "Pressurized Delivery" as pressurized transport to the lab.

Depends on how hot the barrel gets in transport to the lab!

 

[adelorenzo]

I do wet mount scanning and it just occurred to me that a glass sandwich would probably not work. It would be difficult or impossible to get bubbles out.

Your sandwich would be glass, fluid, negative, fluid and a sheet of clear mylar on top.

If you consider the ongoing consumables cost of fluid and mylar it's probably just worth buying some AN glass.

 

[Photo Engineer]

Kodak used a special negative carrier for fluids and used a variety of silicone oil when they wanted a "wet" mount. I don't know any more of the details than that.

PE

 

[Bob Carnie]

Dear ChrisBCS,

Focal Point is a great source for negative carrier glass sets. I bought a set in the last year for my Omega D5 carrier and it fit perfectly.

While I've used Edwal No-Scratch quite a bit on old negatives, I've only used it once with a glass carrier. There were no issues.

Good luck,

Neal Wydra

Focal Point is excellent they will sell you the top AN and Bottom regular for your glass carrier.. highly recommended.

 

[AgX]

Kodak used a special negative carrier for fluids and used a variety of silicone oil when they wanted a "wet" mount.

I would not want any silicone oil near my darkroom.

 

[Christopher Barrett]

If you really want to try wet mounting, I'd get some Kami fluid from Aztek. It's what I use to mount on my drum scanner. Kami fluid is nothing like the oil that used to be common for drum mounting. Though it doesn't contain alcohol, it dries similarly. Once you pulled the neg out of the carrier, the fluid would evaporate in seconds. It's not messy at all, unless you spill it.

 

[ic-racer]

Something with a high boiling point that does not evaporate. Something like microscopy oil. It would probably ruin the negatives that is probably why you [or I] have never heard of it.

 

[GRHazelton]

Chatting with an old newspaper photog, from the 4 x 5 days, he mentioned that they used a dusting of corn starch (!) with glass negative carriers to forestall Newton's rings. I can't offer any more details, but it would be cheap enough to experiment with, and shouldn't damage negatives....

 

[AgX]

I think we should differenciate between:

-) fluids for pristine films (just to avoid Newton-rings)

-) fluids to cope with scratched bases and emulsions (would cope with Newton-rings too)


Furthermore we should consider whether the fluid

-) harms the base

-) harms the dyes

-) will diffuse into the emulsion

-) will evaporate completely

-) will leave a mess, if not evaporating

-) is flamable, toxic (though we typically would use only tiniest volumes)



That all gives plenty room for experimentation...
But the Kami site is a good point to start from.

 

[ced]

Try Zippo lighter fluid or petroleum ether both evaporate quite quickly once the slide/film is lifted, you need to tape all four edges down and 1 sheet of glass is enough to keep flat.