C-41 Developer and Blix stability

[MEB]

Hello all,

I am so far successfully using the C-41 film development kit to develop my 35 mm color films. I keep the solutions in well closed glass bottles filled to the top. So far the chemicals seem pretty stable there, but I wonder how do I see when one of them - either developer mix or Blix - decomposes? I would expect to see a color change in the yellowish developer, but how do I know if the Blix is still okay since it has a dark red color? Any precipitate appearing at some point? Also, I see a little bit of brown precipitate formed in the developer storage flask, but it fully dissolves when heated up to 39 deg C. I suspect this is normal?

Other question related to this: can I use the same Blix prepared for RA-4 printing process also for the C-41 development and vice-versa?

 

[trythis]

When I developed c41 with blix, (vs bleach then fix) it was dead after 2 hours. I don't know how yours is lasting more than a week. The bleach and the fix are basically attacking each other so air seal has little to do with their longevity. This is my vague understanding from reading 10's of c41 blix vs bleaxh fix discussions. Maybe I missed something.

 

[bvy]

Developer is easily tested with a clip test. Take a piece of undeveloped color film and drop it in the developer before using it. If it turns black after several minutes, you're good. If in doubt, throw it out.

I would not use RA-4 blix for C-41. In fact, I wouldn't use any blix. Separate bleach and fix is the way to go.

 

[MEB]

When I developed c41 with blix, (vs bleach then fix) it was dead after 2 hours. I don't know how yours is lasting more than a week. The bleach and the fix are basically attacking each other so air seal has little to do with their longevity. This is my vague understanding from reading 10's of c41 blix vs bleaxh fix discussions. Maybe I missed something.

This doesn't agree with my own experience here. The Blix in fact seems quite stable here - I am already using it since 6 weeks (developed 4 films with it), always pour it back into the flask, fill it to the top and reuse it. No color change, no precipitate either. Film development works perfectly.

I read about some of the Blix vs. separate bleach and fix discussions. I am not convinced that this is an immediate must-do to keep them separate. What I have seen is that there seem to be sold different bleach materials - one is Fe(EDTA), the other is Fe(CN)6. I have the Fe(EDTA) one which is a very stable compound. This could explain why people see different stability with Blix.

 

[Photo Engineer]

Ferricyanide blixes go bad in hours, but ferric EDTA blixes can keep for weeks or months depending on storage. BUT, blix ingredients always interact and lead to decomposition, even when unused and in a closed bottle. The symptom is formation of a precipitate in the blix.

Keeping varies so much depending on use and conditions that it is hard to say. The clip test described above is good and a clip test of fully developed B&W film dunked in blix is good to test the blix. Clearing should take place in a given time based on the formula.

PE

 

[MEB]

Ferricyanide blixes go bad in hours, but ferric EDTA blixes can keep for weeks or months depending on storage. BUT, blix ingredients always interact and lead to decomposition, even when unused and in a closed bottle. The symptom is formation of a precipitate in the blix.

Keeping varies so much depending on use and conditions that it is hard to say. The clip test described above is good and a clip test of fully developed B&W film dunked in blix is good to test the blix. Clearing should take place in a given time based on the formula.

PE

Excellent, thanks for confirming my suspicion in regard to the bleach components. Okay, I will watch out for some precipitate in the Blix flask. I will keep the clip test in mind, too - simple and effective (thanks bvy!).