Questions about developers

snark · 2025-07-17T10:15:30-0500

Being a rank amateur hobbyist, I don't shoot enough film to warrant mixing gallons of developer at a time and letting much of it expire, so I broke down a gallon of ID-11 powder into four parts, sealed them in vacuum bags and stored them in a cool, dark environment. Over time, the powders started turning darker, and my latest batch of this stuff yielded consistently thin negatives. Maybe I should start using Diafine and mixing the whole gallon, as it has a very long shelf life. Any other suggestions?

The Diafine instructions recommend exposure index of 250 for the film I'm using (FP4+). What does that mean?

gk fotografie · 2025-07-17T12:27:30-0500

snark said:
Being a rank amateur hobbyist, I don't shoot enough film to warrant mixing gallons of developer at a time and letting much of it expire, so I broke down a gallon of ID-11 powder into four parts, sealed them in vacuum bags and stored them in a cool, dark environment. Over time, the powders started turning darker, and my latest batch of this stuff yielded consistently thin negatives. Maybe I should start using Diafine and mixing the whole gallon, as it has a very long shelf life. Any other suggestions?

The Diafine instructions recommend exposure index of 250 for the film I'm using (FP4+). What does that mean?

I don't know how much experience you have with developing film, but I wouldn't necessarily recommend Diafine to less experienced people. It's a two-bath developer, so you're not just making one gallon when you mix it, but two separate one-gallon developers (Bath A and Bath B) that you have to use one after the other in the same development run. Also, keep in mind that Diafine is incredibly expensive and usually quite hard to come by, at least in Europe and perhaps also in the US.
While this developer is excellent once you get the hang of it, I would personally opt for something else (and a smaller package!). Also, realize that cross-contamination, if even a little bit of Part B ends up in Part A, is disastrous — you can simply throw away the entire Bath A — and you don't want that with a developer this expensive. Exposure index (EI) actually means the ISO value, ASA (American Standards Association) is actually a fairly old name, as is the old German DIN (Deutche Industrie Norm), but the ultimate meaning is the same for all. (by the way, opening either a liquid, mixing it with water or mixing a powder means that air has been introduced, regardless of whether you seal everything airtight immediately afterwards, so a long shelf life when you mix Diafine A+B with water and store it is rather wishfull thinking)