2 Films You Should Not Develop in DF96
These two films result in totally clear negatives — and possibly ruined developer
Cinestill’s DF96 Monobath is an extremely versatile — and generally very forgiving — single bath chemistry. It works great on traditional-grain films like Kodak’s Tri-X or Kentmere 100. And it even does a good job on T-grain emulsions like Kodak T-Max, with some modifications to development time.
If you’re in a hurry, in the field, or just don’t want to deal with the hassle of a separate developer, stop bath and fixer, DF96 is almost always a great choice to develop black and white film. It produces archival negatives, and has the added benefit of developing a reel of 35mm film in about 4 minutes.
But sometimes, it’s important not to use DF96. Two films in particular appear to simply not work at all with the chemistry. It’s important to choose other methods for developing these films. Otherwise, you risk losing whole reels, and the time and effort that went into shooting them.
Adox CMS 20 II
Adox CMS 20 II is a professional, low-ISO film with a clear film base, which is often exposed at speeds as slow as 6 ISO. It’s notorious for being one of the most difficult commercially-available films to shoot properly. And it can also be challenging to develop.
The datasheet for DF96 actually provides an entry about CMS 20 II, which notes that it should be exposed at 3 to 6 ASA when developed with a developer other than Adox’s proprietary Adotech. It doesn’t actually say, though, that the two are incompatible.
In my experience — and based on perspectives from others in the analog film community — DF96 and Adox CMS 20 II simply don’t work together. I shot a reel of CMS 20 II and tried to develop it in DF96 in my LabBox. The result was an aggressively darkened developer, and an almost totally clear film with just the tiniest trace of a developed image. You can see what it looked like in the image at the top of this article, which shows my CMS 20 II after development in DF96.
Here’s the only even semi-visible image I was able to recover from the basically-transparent film. Even this is helpful to see, because it means that I can be positive I loaded the film correctly in my camera, and didn’t inadvertently run a whole reel through without actually exposing it.
As best as I can tell, the DF96 caused the emulsion to totally separate from the film base and wash away, or simply dissolved all the silver off it. Asking around in the community and reading some forum discussions, there could have been several reasons for this, such as the PH of the DF96, or the fact that it includes an integrated fixer, and so after using DF96 for 5+ rolls and increasing development time to 6+ minutes, the DF96 was severely over-fixing the sensitive film.
There was also a suggestion that the temperature was simply too high to properly develop the CMS 20 II. I tested that theory by developing another reel of the film in 1:100 Rodinol at 75 degrees F, which turned out fine. So I doubt temperature was the issue.
Any of the other factors could have accounted for CMS 20 II’s failure in DF96. And when I reached out to other photographers, they shared similar experiences of ending up with a totally-clear film strip after combining the film with DF96.
Again, this is surprising, since DF96’s datasheet specifically mentions CMS 20 II. Either this should be removed, or there’s some other factor at play (like needing to use fresh DF96 to develop CMS 20 to avoid overfixing). Either way, to avoid the risk of ruined film, I’d advise using different chemistry when developing CMS 20 II.
Silberra ORTA50 is an orthochromatic film, designed for optical printing. It’s also a slow emulsion, but not nearly as slow as CMS 20 II. Like CMS 20 II, though, it’s also considered a high-resolution film with almost non-existant grain.
And like CMS 20 II, it apparently does not work in DF96. I say “apparently” because I have not shot ORTA50 myself. But reports indicate that the same issues which affect CMS 20 II affect ORTA50, too. The emulsion appears to dissolve into the developer, and the strip comes out almost totally clear.
Silberra says on their website that “first coatings of ORTA were real problematic: emulsion was going off the substrate, as ISO80 sensitivity gives new qualities to the emulsion (e.g. viscosity is completely different) so Micron had to find right adhesive and hardening component dilution to provide both nice emulsion quality and good adhesive properties.”
Those issues with adhesion may still persist when the film is used with DF96. Again, as with CMS 20 II, it’s probably best to choose a different chemistry.
DF96 is generally extremely versatile and forgiving, and can be used with a wide variety of films. But for these two films, it’s likely not a good choice.
Luckily, there are plenty of other options available to develop these emulsions. Adotech or Rodinol work for CMS 20 II. And the following developers are approved for for ORTA50:
- Silberra Ascorol — 7 minutes @ 1+29
- Kodak D-76–7:30 minutes @ 1+1
- Ilford ID-11–7:30 minutes @ 1+1
- Kodak X-Tol — 7:00 minutes @ 1+1
For films like Tri-X and even T-Max, go ahead and use DF96. But it’s probably safest to make a different choice for CMS 20 II or ORTA50