2791 9" film that's a mystery!

[Mogsby]

Hi,

A friend of mine has bought a cannister of what is assumed to be Aerographic film, but neither of us can find any information on it!.


With a test of fixing the film only, it has a pink film base.

Perforations are along one edge only!.

Any help or pointers will be more that appreciated.

Cheers

 

[mshchem]

That's a standard size for the old aerial cameras

 

[138S]

That's a standard size for the old aerial cameras

Specially used for military aerial cameras like the Faichild K-38.

The U-2 spy plane used 1800m reels of this film format.

 

[Donald Qualls]

Nice! Next question, how much fog has it racked up? That 155 feet is more than two hundred 8x10 sheets -- about two thousand bucks worth of expired fun.

 

[Andrew O'Neill]

Being aerographic from, does that make it infrared?

 

[Donald Qualls]

Being aerographic from, does that make it infrared?

Probably not, or it would be marked as such -- but many aerographic emulsions had "extended red sensitivity" like Tech Pan -- reds will photograph lighter, blues and greens darker than they would on standard panchromatic emulsions.

 

[Kodachromeguy]

The extended red sensitivity was designed to penetrate mist or fog compared to regular panchromatic film of the era. I wonder how you can test this film? Cut 4×5 sheets possibly?

 

[Donald Qualls]

Could also cut a 61mm strip off the end and wind it up into a used 120 backing. That would give enough length (about four frames of 6x6) to shoot a bracket for speed testing.

 

[Andrew O'Neill]

There are some aerographic Plus-X with extended red sensitivity (looks like out to about 720, like Konica), for a decent price. Tempting me...

 

[Mogsby]

Nice! Next question, how much fog has it racked up? That 155 feet is more than two hundred 8x10 sheets -- about two thousand bucks worth of expired fun.

I have no idea of how fogged the film will be and no idea of age!.. Any suggestion what developer to use?. also developing time!.

 

[Mogsby]

Could also cut a 61mm strip off the end and wind it up into a used 120 backing. That would give enough length (about four frames of 6x6) to shoot a bracket for speed testing.

Hi Donald,
I must have skipped over this comment!. It's a really good idea, but where would you suggest I start exposure wise. With no information available on the film, I have no idea what it's original speed was, it's age or even what developer to use and processing times and temperatures. Do you think it could be a Kodak film due to it's emulsion number convention?. My friend lives 200 miles away, so I have to wait for her to spool some off and send to me before I can do any testing myself.

 

[Donald Qualls]

@Mogsby I think it's highly likely to be a Kodak product; they pretty well own the USG contracts back in the day. For age, it might be anything from 1950s to 1980s vintage, I don't see any reliable way to tell. I'd suggest developing an offcut to check fog.

Start with a drop test: cut a snip, and in the light, put a drop of developer on the emulsion. Time how long it takes to turn full black, and develop with normal agitation for five times that long as a starting point. Cut another snip (or a 61mm strip off the end, so you can load it into a reel), develop for that starting point time without exposure and compare the result to your fixed-out snip. That'll give an idea of fog.

Once you know how bad the fog is, you can make a guess at speed -- cut another 61mm strip and load it up in a 120 roll, and shoot a bracket. I'd start with EI 25 and work up in one stop increments; you should be able to get 25, 50, 100, and maybe 200 on one strip. What you get for results will tell you if you need another strip.

The beauty of this compared to the usual "I got some oddball film of unknown age" is that you have a bunch of it, not just a single roll or even two or three rolls. You've got five hundred feet. You can afford to spend some in testing.

EDIT: Oh, forgot to add, any B&W developer should work. I'd probably start with something like D76 or Xtol -- though it was probably originally intended for a super fine grain soup like Microdol.

 

[Mogsby]

@Donald Qualls
Many thanks for the tips etc. I'll pass this to her and hopefully soon I'll get some to test myself.
Cheers

 

[mshchem]

Specially used for military aerial cameras like the Faichild K-38.

The U-2 spy plane used 1800m reels of this film format.

I bought this thing to try to process roll color paper. Still getting around to this project. But this sort of machine could be used to develop these short rolls of recon film.