Technical question: E6 in C41.

[fotoobscura]

Evening.

Having a few rolls of E6 left that I didn't feel like spending $10/each to develop, and knowing that whatever was on them didn't mean much, I went ahead and developed two rolls of Velvia 50 and Elitechrome 160T in C41 chemistry.

They came out pretty well and I forgetting that this was E6 and not C41 (e.g. I should have done this one shot), I poured the used chemistry back into the bottles (dev and blix) and essentially contaminated the existing c41 chemistry.

The next day I developed a roll of Superia 800 (C41) in the same chemistry and all came out well.

Then, a few weeks later, I went to develop two rolls, both C41, and they were completely cleared.

It took me a few days of pondering before I figured it must have been the E6 film in the C41 chemistry that caused it to clear.

So the question is for someone technical: what happened chemically in this longer period of time to cause what appears to be a complete breakdown of the developer? I can only assume the blix cleared the roll completely because the developer wasn't acting at all.

Thanks in advance!

 

[OzJohn]

Not sure why you'd pose this question on a digital/hybrid forum - most of the photo chemists who could most likely help you post on APUG and don't seem to visit DPUG. Cross processing of E6 film in C41 used to be commonplace and most most labs did it using the same chemistry line as they used for straight C41 so I'm not sure that cross-contamination is the problem. OzJohn

 

[fotoobscura]

I posted this on APUG in the Color: Film, Paper, and Chemistry sub-forum.

 

[heterolysis]

I've heard E6 can ruin C41. Most labs will run cross processing at the end of the day before they dump the chemicals. So I'm told.

It's likely your chemistry was fine after cross processing, but that whatever is in the E6 catalyzed some sort of decomposition of your developer (oxidation?) and that after being left a while it got to the point it was no good anymore. That would be my guess, but I don't know a thing about E6 chemistry so hopefully someone else can come along and shed a little light on it for us.

 

[Simonh82]

It wasn't the E6 that ruined the film. I've had both Tetenal and Rollei chemistry last for months after putting E6 film through. It sounds more like you've mixed up your dev and blix.

Most commercial labs operate a replenishment system so the chemistry is rarely dumped.

It just isn't going to cause this kind of problem, nor does C41 developer just die like that.

 

[fotoobscura]

Simon,

Thanks. Fair enough. That was my other thought and it makes sense considering reusing C41 chemistry after developing E6 film gets much darker (especially the dev).