Aerial Film

[BarryS]

I posted earlier about building a simple 5x24 camera, but first I need to find out a little information about my aerial film, I have three rolls, 350 ft of Plus-X Type 2401, 250 ft of Anscopan, and 100 ft of Kodak High Definition Aerial Film SO-243. Is anyone (Jim?) familiar with these films. The Plus-X is on an Estar base, the Anscopan on "Reconaissance Safety Base" (another thin base?), and the SO-243 on "Gray Base" (is that normal acetate?). Do these films have an anti-halation backing? Any ideas on EI's and developers? Looks like these were stored in a basement, so I'm wondering about developers that might minimize fog (if that's an issue). How about the leader on the Anscopan? Is that 20 ft of clear base--10 ft on each end? I'd like to run some clip tests with this stuff, but any advice would be appreciated. Thanks.


http://img292.imageshack.us/img292/2168/aerialfilm1ci0.jpg
http://img208.imageshack.us/img208/1990/aerialfilm2lo0.jpg
http://img136.imageshack.us/img136/302/aerialfilm3lf7.jpg

[David Vickery]

I bet you will get a lot of fog!
I would try cutting some down to 4x5 and trying it out in the backyard with your standard developers to start. You will probably benefit from some benzotriazol added to the developer with the age of the film being what it is, and maybe you need a lower PH developer as well, compared to what you may be used to, to help cut down on fog.
I would certainly give that a try though. And mess around with it some, a 5x24 camera would be well worth the effort to see if this film could be usable. Not too long ago someone on ebay was selling a bunch of fresh aerial film in 5" and 9.5" rolls. I can't recall the seller at the moment and I don't know if he still has any of it. I believe that Jim Galli got some of the best of it. He probably will be able to give you some good advice about this. I have some of the 9.5" film but have still not even tried it out yet.

[BarryS]

Thanks David. Guess I'll just cut a few test sheets and see what happens. Can you recommend a low pH developer. I've standardized on Pyrocat HD for sheet film and XTOL for roll film, but I haven't any idea as to the pH of either developer. I figured the Pyrocat wouldn't be the best choice for potentially fogged film.

[Martin K]

It was 27 years ago but I was an aerial photographic tech in the South African Air Force. I can tell you a little about aerial film, what I remember. Aerial film was designed to have a very low base fog, that is the density of unexposed developed film. This was to keep shadows as clean as possible. The film was also pretty flat to give it a very long even straight line portion to the curve. All of this of course to allow the maximum detail to be extracted from the images. The rolls were processed through a Kodak versamatt roller processor and had a tough base that was pretty resistant to damage. We did some experiments with very alkaline developer to speed up the processing time. The theory was as long as the film was wet the silver grains would migrate towards each other and clump. The very fast developing time surprisingly (to me anyway) did result in a very fine grain structure when accompanied by very fast fixing and a hypo clearing agent and shorty wash. We used kodalk, a proprietary Kodak accelerator, to increase the alkalinity of the developer.

We used to determine developing time by exposing film to a densitometer and plotting a D LOG E curve to dtermine film speed and so on. A bit complicated and you would need a densitometer and sensitometer. Exposed aerial film would be clipped and a short piece processed to determine shadow and highlight density in order to calculate an optimum dvelopement time.

[BarryS]

Thank you Martin. It seems like using an alkaline developer will have multiple advantages. Unfortunately, I don't have a densitometer, but with some clip tests I should be able to get a feel for the film speed. I may try developing in some XTOL with a bit of sodium metaborate and benzotriazol and see what happens.

[David Vickery]

I'd try a few sheets in straight Xtol and then some with the added stuff and see what you get. Based on what Martin said it sounds like you have a good chance of great results. I don't know off-hand what the chemical makeup of Xtol is and whether it will work well with the added chemicals, but I think it is certainly worth a try. I am currently trying out a low PH developer with Amidol.

[David Vickery]

Upon further reflection -- I was thinking in terms of what I am trying with Amidol, since I have a bunch of it. Amidol will process film in an acidic or near acidic (low PH) environment. But if you don't already have a bunch of Amidol then it would not be worth trying to get some. The Xtol is probably one of the better choices for experimenting with your film. Using a fast development time and low temperature should result in fine grain and maybe lower fog with the idea being that the longer the film is in the soup the more time it has to build fog. But I would want to try it out with the standard Xtol concentration and development and that you normally use just to see what that gives you, and to have a basis of comparison.

[BarryS]

Thanks David--that sounds reasonable. I just found out that MIL-F-32 was a government specification that included:
AERIAL
PLASTIC POLYESTER
BLACK AND WHITE
NEGATIVE
PANCHROMATIC EXTENDED RED;

So the "reconnaissance safety base" is another polyester base like the Estar base on the Plus-X. The SO-243 seems to have been used as a holographic film.

[Martin K]

What would also help I think would be to use a zone calibration protocol. There is probably a ot of info on this forum about this topic. You would then not need a sensitometer and would quickly and accurately establish a film speed and developement time.

Good luck. I would love to see the results.

Martin