JohnSwanda Loc: San Francisco

In the film days, we always thought of increasing or decreasing the percentage of development time to push or pull the film. Adding 20 seconds would be meaningless if you didn't know what the normal development time was.

radiojohn

Edwal used to have it in liquid form and there were tablets. I think it was also used if, for example, you accidentally shot ISO 400 film at ISO 100.

radiojohn

There used to be something called restrainer that helped cut chemical fog in old exposed film.

https://www.bhphotovideo.com/c/product/123748-REG/Photographers_Formulary_10_0250_10G_Benzotriazole_Anti_Fog_1.html

Ron Dial Loc: Cuenca, Ecuador

How has it been stored, and was it in a low humidity environment? That is the key.

ecurb Loc: Metro Chicago Area

Steved3604

With old film the key is what temperature for how long. Cool/cold and relatively dry are good. Room temperature is OK. Hot attics or out buildings (especially in year round heat) are not so good. Development sooner rather than later is best.
Fairly cool chemistry temps are good -- probably not over 73 degrees. I agree that 20 percent additional time should be helpful on this old film. Also, I would recommend a 2-4 minute water pre-soak to get the (old/dry) emulsion ready for the developer. I just use clean water at about the same temperature as the developer for about 2-4 minutes with light agitation. Be sure to drain all the water out. D76 is a good universal developer or use whatever the manufacturer recommends. A good, long wash to remove all the fixer is suggested -- maybe 50 percent longer than recommended/usual. The negatives will probably have "base fog" due to age. You can probably scan "through" the base fog and hopefully have a useable image. If concerned with all the info and recommendations you can always do a "tail test" of maybe one or two images from the tail of the film at your best guess for all conditions before developing the whole roll. Be sure to get at least one image -- and Mr. Murphy guarantees that you will always cut through the best image and the image you wanted. Good luck and let us know what happens.

aschweik Loc: NE Ohio

Thanks to everyone for their advice! I bought the film on eBay so I have no idea how it was stored. The camera takes 2 Rapid cassettes which it didn't come with. I found an empty one and then got the film for the other one. I think it's regular 35mm film but a modern 35mm roll doesn't fit the camera. Pretty sure you can take the film from a regular roll and thread it onto the Rapid cassette if you really wanted to (I don't). Plus it only takes 16 frames.

The camera was from the personal collection of Eaton Lothrop, as was the film. I'm only using the one roll I bought (came in a set of 5) and I'll save the rest as "historic".

aschweik Loc: NE Ohio

Great information, thank you!

MrPhotog

The rapid cassettes are basically 35 mm cassettes without the rotating spool on the center. They use short lengths of regular 35 mm film.

Like old box cameras you put the fresh fulm cassette on one side of the camera and an empty cassette on the other side. Some cameras were self threading: pull out just enough film to get it to engage with the drive sprockets and close the back. Other cameras needed you to pull out an inch more and start the end into the receiving cassette.

The drive sprockets pushed the exposed film into the empty cassette. Once all the photos were taken on a roll, you pull put the filled cassette, put the empty cassette in its place and dropped in a fresh cassette.

You might, or might not have a small tab of film sticking out of the receiving cassette. If you do, great. In the darkroom or in a changing bag you can just pull the film out to load your developing tank. Then you can reuse the cassette by just pushing in fresh film. Otherwise you’ll end up destroying the rapid cassette to get the film out.

To ensure you have that excess tab of film hanging out (so you can reload and reuse those cartridges) don’t shoot all the pictures on the roll of film. If you have a 16 exposure roll, just shoot 13 or 14. Then advance 2 blank frames to get your last picture safely into the receiving cassette, and open the camera. Pull out the cassette with your exposed film and whatever was left in the supply side will come out of that cassette and be easy to grab. Note: when you do this be careful to not get confused and put a roll of exposed film back in the camera.

Keep the cassettes clean and you might be able to reuse each one a dozen times. Put ‘em in your museum when you start getting scratches on your films from grit.