Life expectancy of C41 Tetenal Colourtec solution

[Colin D]

I exposed a couple of Portra 400 4x5 sheets on the weekend and developed them using Tetenal Colourtec solution that has been stored for about six months. The sheets came out blank , I did them seperately but got the same result for both. I stored the solution in the proper plastic well sealed bottles, not refrigerated and have used the solution on and off since mixing it. In between uses I fill the space in the bottle with butane gas. Is the solution too off or has something else gone wrong? If I hold the sheets up to a light I can see through them but there is no sign of an image, nothing at all. But the odd thing is the side with the emulsion on it still has that mocha opaque look to it when not held up to a light. I'm guessing it is the solution that is the problem but not sure.

Thanks

[Michael_qrt]

Did the film edge markings develop? If they did then it would point to an exposure problem but if they didn't it sounds like a developing problem. Can't really say what happened to the developer but contamination might be a possibility, It might not take much of the right contaminant to ruin the chemicals. Someone more experienced than me might be able to determine from your description of the negs whether it's a problem with the developer or the blix.

[spacegoose]

I wouldn't use mixed C-41 developer older than 1 month. BTW, I think refrigeration is good for mixed developer.

[Sevo]

Depending on the storage conditions and grade of depletion, I have experienced one to four weeks without visible degradation, with the preceding Tetenal C-41 "Press Kit". The current Colourtec is a bit more modern in formulation and might make it for a few weeks extra - but six months is steep indeed, I would not expect that to work at all except when storing mxied but unused chemistry refrigerated in completely gas tight (glass or multi-layer) containers.

[Colin D]

Looks like the mixed solution is too old. Thanks for the feedback, that makes my option simple.