An Unknown Positive Microfilm

As film prices have risen recently, people have been looking for cheaper alternatives of film to choose from. A lot of these fall into the category of low ISO microfilms. These are commercial films not intended to be used in conventional film cameras; mainly used in documentation, reproduction, and copying. When talking about Kodak ‘industrial’ films, they tend to forgo standard names and rely on a number, I believe correlating to the emulsion. One such microfilm was a very unique stock, the Kodak 2468 Positive Microfilm. This film has a very unconventional look to start. The unprocessed film is vibrant red in color with a clear base that you can see right through. Once processed with normal black and white chemicals, the film comes out as a positive image. An incredibly special film stock, and the closest resemblance I could find to what I was working with. This was my experience of testing, and the long journey of trying to get an image from an unknown microfilm.

The First Test

Initially, I had no idea if this film would produce an image or what one might look like. I was unable to find any reference to what a developed positive microfilm negative looked like. Would it have a clear base like other microfilms, or was it going to stay red? To be honest, I didn’t even know if this was Kodak 2468. I ran across this film inside of a bulk loader that I bought with no markings of the stock or speed. The color of the undeveloped film matched Kodak 2468, and I had a reference to an ISO/developing time online. This was 0.6 ISO and 6 minutes in D76. I thought a reasonable equivalent would be 1:32 HC-110 for 10 or so minutes.

I was thinking I would get a faint image and fine tune from there. What I actually got was nothing. Nothing but an oddly colored yellow base with what seemed to be black spots on the edges. I failed to realize there was a large gap on the bulk loader between the lid and side and I quickly taped up the gap. Hopefully the film was still usable, so I gave it another try

The Second and Third Test

I wanted to see if I completely exposed the film to light in a sunny window and developed normally, that I would get the same result of standard negative film. Maybe it was some strange incompatibility with the HC-110. I threw the negatives in some D96 for around 10 minutes and I was hoping for a dense all black image. What I got was very different.

Gone was the yellow sickly color and now I was getting a light pink. This baffled me and I had no idea why I was getting no image whatsoever. I was starting to believe that the bulk loader was completely exposed. A few days passed, and I realized that I failed to remember that this was a positive film. Clear should mean over exposed, so this would be the correct result. A waste of time in hindsight, but a useful test of another developer.

The Fourth and Fifth Test

HC-110 is my go to for expired and found films. One formula that has helped me with particularly difficult films is, HC-110 at 1:100 stand developing for an hour. I tried shooting bright windows and hoped for an image of some sort. Sadly nothing but the same result, a yellowish clear base with black spots, and no hint of an image. I would have to modify either the exposure or development excessively. Since I was already Shooting at 0.8 ISO, I decided that the variable worth changing would be the developer.

At this point, I decided that I would get an image out of this film no matter what. I tried taking long exposures of lightbulbs with the same 1:100 ratio again but stand developing for twice as long, two hours. This time the film came out completely different. Closer resembling a regular black and white film base, with the slight image of a ceiling light. Very faint but finally a baseline to work from. Success, but a short lived one.

The Sixth Test

Sitting at my desk one night I had an epiphany. This is a positive film, that would work amazingly inside a stereo camera. I took my Stereo Realist f/2.8 when visiting my parents and took shots in the extremely bright sun. I decided that stand developing for three hours may be the magic number for a 1:100 ratio of HC-110.

This is when things took a different turn. I tried the same dilution but a longer time, expecting a darker image and better exposure. What I got a completely different looking result than the last time. The negative was much lighter than before, but I was introduced to a bigger problem with the film… mold, and a fair bit of it. The film must have been stored in a moist environment for quite some time, causing mold to be etched into the base. I decided to store the bulk loader inside a ziplock bag along with the developed film.

I assume the image is darker by the mold spots possibly because of something to do with the acidity of the mold, or the mold was covering the film when the bulk roll was exposed to light. When working through these initial experiments, there was something I kept forgetting. Everything is opposite with positive film. There should be distinct dark separations between frames. I wanted to try the same experiment again to see if I could get some of the same darker images with longer exposures.

The Seventh, Eighth, and Ninth Test

I’m almost certain this is Kodak 2468 or at least one of the similar stocks Kodak produced. The odd part is the developing times. I've tried what sources stated online, but my results were drastically different. The reason these times are longer is most likely the result of the roll being exposed to light briefly and the environment it was stored in. I’ve worked with microfilm before, and this was putting up the toughest fight. I was determined to the best image I could from this stock and give this film a chance it never got. With new resolve, I decided to try a few more tests, increasing the HC-110 in each cycle. Pointing the camera at bright windows again, I tried developing the film in HC-110 at a dilution of 1:50 for three hours, 1:32 for three hours, and 1:15 for two and a half hours.

The results were getting much better, but I still had to really increase the contrast when scanning. You can finally see greys and definition on the 1:15 negative. I felt that I was extremely close to figuring out a workable formula. A bit more HC-110 was needed, and as much light as possible. For my next test, I would try taking pictures outdoors on a very sunny day.

The Tenth and Final Test

The day came with intermittent clouds but intensely bright sun. I chose a fast f/1.9 lens and did not bother with a meter. I shot consistently at 1/30th of a second, about as slow as I can handhold. The film was then developed in HC-110 at a dilution of 1:10 for two and a half hours. The resulting negative was different than I had seen so far. When looking at the negative in the light, it had a sort of metallic sheen. The scans were the best yet with a bit of contrast and brightening.

All of the pictures turned out to have lots of detail, much better than I could have hoped for. Quite the unique look to them with the incredibly darkened edges. Scratches, holes, and fingerprints are present on these scans; I believe it adds to the almost rough nature and character this film brings. Beautiful in my opinion, and I really like the shot of the building with trees in front. These were the best images so far and I felt a good stopping point to review my findings and catalog my journey.

The Final Thoughts

If your looking to develop Kodak 2468 or any other positive microfilm, give the standard formula found online a try first, 0.6 ISO in D76 for 6 minutes. If you had no result like myself, give 0.8 ISO in HC-110 1:32 for two hours a shot. Finally, if the developed film still needs improvement, try 0.8 ISO in HC-110 1:10 for two and a half hours. These three formulas will help give you a great start in the positive microfilm world.

I plan to keep this stock around and try some more tests in the future with flash photography and possibly portraiture. An unpredictable film may be an interesting addition to work like that. This was quite the undertaking and I hope you enjoyed following me on my journey with this unknown positive microfilm. It was a long time in the making, but an exciting and different experiment to undergo. If I learned anything, it’s that any film has the ability to produce incredible images, it just may take some time.