E6 First Developer: when is it too dark?

[afriman]

I have two unopened Tetenal E6 kits that have been sitting on my shelf for almost two years. Judging by appearance, only one of the kits' First Developer looks like it may not be usable any more. Here's a close-up of the two bottles, with the manufacturing codes:

Interestingly, according to the codes, the one on the left is about six months "younger" (March 2017) than the one on the right (August 2016), and yet it shows much more oxidation. I assume this is probably due to different storage conditions before I acquired the kits -- or perhaps that bottle wasn't sealed as effectively as the other one?

Anyway, to my eyes the developer on the left is now beyond the "pale straw" color that is usually given as a rule of thumb, and I should rather not risk any important film with it. I'm just wondering how this compares with other users' assessment and experience. Would you also discard Tetenal FD when it has reached that color? I know it's difficult to provide a definite answer because of variances between different displays, and I know I should really be testing it myself. Still, I'm curious to know what others think.

 

[Rudeofus]

I have made the experience, that E6 FD fails slowly - it simply loses activity more and more until you end up with really dark slides. You can compensate by increasing concentration and/or increasing FD times, but at the same time risk color cross over. If you want to play with aged E6 kits, you need to find a test procedure for FD. Note, that E6 FD makes a very strong B&W developer, therefore you don't have to waste expensive slide film on tests.

Unless you are ready for pre-testing or nasty surprises, I would not use FD concentrate with any kind of discoloration. I've wasted way too many rolls of slide film to being cheap&careless.

 

[afriman]

I can get some fresh First Developer from a local manufacturer, but it's made for the standard E6 7-step process. I assume there's no difference between that and a three-step kit's first developer?

 

[Rudeofus]

E6 FD is interchangeable between 3 bath and 7 bath kits. It's the only E6 bath which is.

 

[afriman]

If I use b&w film to test E6 FD, how does the development time and temperature correlate with that of E6 film? In other words, if I get acceptable density and contrast with, say HP5+ at a particular time and temperature, how will I transpose that to the required development time for E6 film? Or can the test only give me a broad indication of how usable the developer is?

 

[Rudeofus]

If I use b&w film to test E6 FD, how does the development time and temperature correlate with that of E6 film? In other words, if I get acceptable density and contrast with, say HP5+ at a particular time and temperature, how will I transpose that to the required development time for E6 film? Or can the test only give me a broad indication of how usable the developer is?

In my experience, if you dilute E6 working solution 1+9 with tap water, it takes about 10 minutes @20°C to develop Tri-X to normal contrast (Hint: this is an excellent developer for slow film, and a great way to use leftover E6 FD). What you need to do is create B&W negative strips with repeatable exposure, and process in diluted E6 FD for some defined amount of time. If you start doing this with fresh E6 FD, you get an established base line to compare future test strips against. If these test strips become weaker, then you need to either increase FD time/concentration, or refer the aged E6 FD to B&W processing and get new FD for E6 processing.

 

[afriman]

Thanks. That's very helpful!