Is it possible to make film sensitive again or at least useful?

Question

I tried shooting some 16mm Kodachrome II film (ASA/ISO 25) that expired in 1973. At first no images came out, eventually after trying all day, I was able to get good visible images on the film after exposing these frames to bright light sources, at f/2.2 (my highest lens opening) the pictures shown below.

Each frame was exposed for 2 1/2 minutes.

This being movie film, would be completely useless in motion scenarios. I have a lot of these rolls lying around and really don't want them going to waste. What do I do with them? Is there some way I can use them?

Answer 1

Kodachrome II 25 speed is essentially a black & white film. After exposure, it was processed as a black & white using a rather typical developer. First a b&w negative resulted. Colored dyes were induced during three more developing steps. All this processing magic is lost to you but you can develop in ordinary black & white chemicals to obtain a b&w negative. Two caveats – the film is slow, only 25 ISO. Typical exposures were made at 1/125 of a second @ f/8. The reverse of this film is coated with lamp black imbedded in an acid binder. This removable jet black backing makes the finished black & white negative opaque. Likely the film remains near 25 ISO. Your poor results could be that you exposed the film from the back side. If so, the Rem-Jet backing will severely block the exposing light. If exposed and developed properly, the Rem-Jet backing will cause the resulting negatives to look nearly opaque. You must remove the Rem-Jet. Soak the developed film is a solution made by dissolving two teaspoons of baking soda in 500ml of water. Soak for 10 minutes and wipe the Rem-Jet off with a soft cloth. Re-wash to remove residual alkaline bath.

P.S. Kodachrome film was made with multiple emulsion layers. Basically, one for red, one for green and one for blue light. The bad news is, all were sensitive to blue light. The solution used was to place the blue sensitive emulsion on top. Under this layer was a yellow filter. This is a blue light blocker that prevented blue light from penetrating further. This filter was made using colloidal silver and named for its creators as a Carey-Lee filter. When the film was processed, a bleach step followed by a fix step removed all traces of silver. The colored dye images remained and this is what comprised the beautiful color image. Your b&W negative is comprised of silver. After the Rem-Jet is removed the Carey-Lee filter remains and gives the film a yellowish perhaps brownish cast. You might lighten it with a dip in bleach-fix (used in the color paper process). You would do this in the light after developing. Caution, this bleach will also take out the silver image that you desire. All you can do is lighten the Carey-Lee. Seems like a lot of trouble when the best you can expect is substandard results.

Answer 2

This may not be the answer you're looking for, and there may be other solutions which one of the technical experts here can think of, but there is a process called "hypersensitisation".

It appears to be a somewhat complex, and maybe even hazardous chemical process, which may daunt those who don't have a good knowledge of chemistry. (I certainly don't and would not want to work with ammonia or mercury vapour).

I've included a link here if you want to have a look at it.

https://en.wikipedia.org/wiki/Photographic_hypersensitization

Don't know if it would work that well with colour emulsions such as your Kodachrome. (As you may be aware, the Kodachrome process was discontinued some years ago). I seem to recall the Kodachrome films required a specialised process which only Kodak and a few select labs had access to.

Out of interest, how did you process that example you showed above - through a lab, or did it yourself ?