E-6 Chem. -> Flakes forming in F.D.

Hello everybody,

I've mixed a 500 ml batch of Tetenal Colortec E-6 from a brand new unopened kit 3 week ago. And made 5 films with it.
... Only to see that there are some weird, supple flakes forming in my First Developer.

At first, flakes were grey, and I filtered them out using a coffee filter. Then 4 days ago white flakes appeared !
What may be the cause and can I filter my FD again to use it ?

What's bugging me is that there aren't any cheap slide films to do tests anymore...

Thanks for reading me

An easy way to test E6 FD is to dilute it 1+9 with tap water and use it to develop regular B&W film (start with 10 minutes @ 20°C for a film like Tri-X). Obviously you'd have to do a reference clip once with freshly mixed chemistry, but after that you'd have a method for testing E6 FD activity without the need for expensive E6 film stock, and you need only 25ml to test in an inversion tank, and even less with rotary processing.

If you process 120 format roll film, 450ml are typically enough to fill a Jobo 1520 tank, so with an initial amount of 500ml you could run two tests over time, and still process 120 film if the test is successful.

PS: the flakes are harmless, but are an indication that your FD has become less active from storage.

Your idea seems logical, I'll tr a BW test with my first developer

Thanks ! I'll keep this thread updated.

Note, that E6 FD is a very powerful B&W developer, which would normally develop Tri-X and the like within less than a minute. Only with dilution of 1+9 - 1+19 will you get meaningful and reproducible results.

Hello again, which dilution do you recommend for the 10 minutes time @ 20°C for a 400 ISO B&W film ?
I have Fomapan 400 that may be sacrified to this task.

Thanks again for your idea !

Try it out. If normally exposed negs look too thin, develop longer or at higher temperature. If negs are too dense, then increase dilution. 10 minutes @ 20°C is a good starting point in my experience.