Can film be developed in gases?

Loose Gravel · Nov 2, 2006

I know to get better edges and higher resolution in the semiconductor manufacturing biz, they have gone to gaseous development. I'm wondering if this applies to film? Can film be developed without an aqueous solution? Any benefit? Practical?

I hope this isn't too stupid a question.

Paul Howell · Nov 2, 2006

Loose Gravel said:
I know to get better edges and higher resolution in the semiconductor manufacturing biz, they have gone to gaseous development. I'm wondering if this applies to film? Can film be developed without an aqueous solution? Any benefit? Practical?

I hope this isn't too stupid a question.

I dont know the answer, but it is an interesting concept.

Jordan · Nov 2, 2006

Semiconductor manufacturing uses solvents and etchants to remove resists, dissolve away silicon, etc. The chemistry there is somewhat simpler than in B&W film developing, where you must get reducing agents to exposed sites and remove byproducts from the film. There are no known suitable gaseous reducing agents, AFAIK.

Gerald Koch · Nov 2, 2006

Certainly, film can be fogged by certain gases. However, for development you need the selective reduction of only certain portions of the emulsion. I don't think that this is possible by using just gases.

jbj · Nov 2, 2006

After an extended darkroom session the day following a trip to the local chinese buffet, I would have to say that, no, gases will not develop film. But seriously, it is an interesting concept. Gas phase kinetics (relative to liquid phase) would lead to some interesting phenomena.

vet173 · Nov 2, 2006

I often have gas while developing film. Hasn't hurt the film and nobody seems to want to bother me.

Aggie · Nov 2, 2006

Would you not need the liquid medium in which to wash the portions of the emulsion sluffed off during development away? Without some sort of medium to transport this off the surface and away, It might develop, but it would all still be intact.

nworth · Nov 2, 2006

The photosensitive resists used in the semiconductor industry are much different from the silver based emulsions used in photography. The grain and resolution of photographic emulsions is largely determined by the structure of the silver grains in the emulsion. Gaseous development would probably not make much difference to the resolution of these emulsions. But in principal, I suppose a gas could be used. Maybe some hydrazine derivative could be used in a high contrast process. Water does play a part in development due to its interaction with the gelatin in the emulsion, however.

richard littlewood · Nov 2, 2006

During the 2nd world war the RAF devised a method of developing film with gasses. I cant remember the times involved but from dry to dry they were in seconds rather than mins (or semi-stand hours!)
It was probably all for speed.

Photo Engineer · Nov 2, 2006

Aggie said:
Would you not need the liquid medium in which to wash the portions of the emulsion sluffed off during development away? Without some sort of medium to transport this off the surface and away, It might develop, but it would all still be intact.

Aggie;

Nothing sluffs off during development.

Dyes wash out and can be washed out at any time. Fix removes the excess silver halide. That requires water, but a stabilzer can be used and no water is needed.

This is an interesting idea, but I don't know what one would use.

PE

Bromo33333 · Nov 2, 2006

Daguerreotypes used gas to sensitize and develop

Loose Gravel said:
I know to get better edges and higher resolution in the semiconductor manufacturing biz, they have gone to gaseous development. I'm wondering if this applies to film? Can film be developed without an aqueous solution? Any benefit? Practical?

I hope this isn't too stupid a question.

Daguerreotype had to be "fumed" with mercury (LINK)

Note that this would not work with a modern emulsion - not that you would want to ... but gasses were used in the past to good effect. I think wet processing was a step in the safe-direction (or safer).

I hear they have made a "safe" version, but I have no details of it.

Loose Gravel · Nov 2, 2006

I know that even film was fumed in the 1920s and 30s to bring up the speed.

Bromo33333 · Nov 2, 2006

Loose Gravel said:
I know that even film was fumed in the 1920s and 30s to bring up the speed.

Are "hypered" films used for astronomy treated with gas to make them less susceptible to reciprocity failure?

dianna · Nov 2, 2006

I'm trained as a chemist and did my graduate research in gas-phase kinetics. The equivalent of "wash" would be to put the negative in a slow-moving stream of an inert gas like argon. Unfortunately at room temperature, most reactions in the gas phase either need very reactive chemicals (safety concerns) or need some sort of catalyst - like UV or visible light. And the apparatus to work with gases is expensive and complex (you'd probably need a gas blower to build it) if you don't want them to contaminate your work environment.

Aggie said:
Would you not need the liquid medium in which to wash the portions of the emulsion sluffed off during development away? Without some sort of medium to transport this off the surface and away, It might develop, but it would all still be intact.

htmlguru4242 · Nov 2, 2006

The safer metod of Daguerrotype development involved exposing the plate to red light for a period of time.

Tom Hoskinson · Nov 2, 2006

Bromo33333 said:
Are "hypered" films used for astronomy treated with gas to make them less susceptible to reciprocity failure?

I heat the film in a sealed chamber that has been evacuated with a hand operated vacuum pump and then backfilled with metallurgical forming gas. This has the effect of removing moisture and some oxygen from the emulsion (sucess is very emulsion type dependent). If the emulsion is amenable to this process, both the effective speed and the reciprocity failure characteristics will improve until the emulsion rehydrates.

David A. Goldfarb · Nov 2, 2006

There is a reproduction method called the Ozalid process that uses ammonia vapors to develop the image.

paul ewins · Nov 2, 2006

Microfiche duplicates were developed with ammonia, but the original negs were developed in conventional chemistry. The duplicates were contact printed using UV light and then run through a box that supplied heat and ammonia. The print time was around a second and developing time was probably ten seconds or less. At least that is what memory tells me, it was twenty years ago.

CRhymer · Nov 2, 2006

My first non-silver process, except for the negative, was an 8x10 contact on diazo paper (not Azo) with UV light (sun) developed by the fumes from 26 degree Baume ammonia (presently costs about $4.00 CDN/litre). Dead simple, and better than my first attempts at gum. But of course that's what got me hooked on alt-process.

CR

paul ewins · Nov 2, 2006

Diazo! That was the stuff. But this was some sort of acetate rather than paper. I think it would have been rather more than 26 degrees too, more like60 - 100 Celsius.

CRhymer · Nov 2, 2006

Diazo is still very much alive in the drafting/architectural repro supply business, as is blueprinting. Diazo paper gives a black or blueline print (black or blue positive on a white or coloured background) as opposed to a blueprint. The 26 degree Baume refers to the strength of the ammonia/water solution. I seem to recall a clear based product as well. Should be easy to find out.

Cheers,
Clarence

gainer · Nov 3, 2006

CRhymer said:
Diazo is still very much alive in the drafting/architectural repro supply business, as is blueprinting. Diazo paper gives a black or blueline print (black or blue positive on a white or coloured background) as opposed to a blueprint. The 26 degree Baume refers to the strength of the ammonia/water solution. I seem to recall a clear based product as well. Should be easy to find out.

Cheers,
Clarence

Ozalid will develop in ammonia vapor. I know from experience. In 1952 I went to work as an aeronautical engineer at NACA. A couple of my office mates had gone overtime to run Ozalid copies of some long oscillograph records on film, only to find out the next morning that the developer had not worked. I knew that ammonia was used int the developing part of the process. I found a bottle of household ammonia in the janitor's closet and a small retouching brush, thinking I could brush ammonia on the faintly visible yellow traces to bring them out. Lo and behold, when I got the brush near the trace, the image popped up! So I put a loosely coiled roll of the ozalid copies in the large drawer of my desk with an open container of ammonia. It worked. Not instantaneously, but it saved an overtime trip back to the Ozalid machine. So everyone in the office made an Ozalid developer out of the large desk drawer, and for a couple of days, evveryone's sinuses were clear.

That is when I earned my nickname "Gadget"

Can film be developed in gases?

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