The internet says Diafine lasts forever. Search, it’s out there all over the place. No one talks time though. They just comment things like “It ran until I contaminated the B solution with A”, or “The volume of A got so low I just mixed up another batch”. That’s great, but I don’t want to know that. This isn’t going to be that, this is going to be dates.

My Diafine was mixed up July 2018. In the following several months I ran thirteen rolls of 120 and fifteen rolls of 135 (I know because I make hash marks on a masking-tape label on the bottle). A couple of the rolls of 135 were twenty four exposure, but the rest were all thirty six. Then, in December, some shit went down and the bottles sat on a shelf in a friends basement until, well, today. Solution A was in a white PTFE bottle and solution B was in a plastic coated amber glass bottle. That wasn’t a conscious choice beyond my wanting different bottles so I could tell them apart, and it was what I had. It also helped that solution B could go in a Brown bottle.

Just ran a roll of Arista EDU Ultra 400. Came out fine. With chemistry that was mixed up four years and nine months ago.

I can’t comment on how long it lasts in terms of rolls processed, I’m sure there are folks who have gone way over thirty rolls and I’m a roll short of that even now. I do feel it’s useful to say after almost five years, it’s still working as well as when I mixed it. Let it be said, the working shelf-life if Diafine developer is at least five years.

One tip I’d like to add though. Solution A will decrease in volume faster than solution B. This is because, in general, solution A is hitting a dry film and absorbing into the emulsion. When you pour solution A back into your stock bottle whatever absorbed into the emulsion stays behind. That can be avoided by adding a minute or two of a plain water soak at the front end of your processing. The water doesn’t noticeably affect the action of solution A and it cuts down on how much of solution A is “wasted” just wetting the emulsion.