Does crossprocessing degrade/damage the developer? (E6 film into C-41 chemistry)

[DavidKKHansen]

Hello.

I've been given a handful of Kodak Ektachrome 160T, which I test shot at ISO 100-50-25-12-6 and then dunked them into C-41 chemistry to be crossprocessed. Looks lovely, the sweet spot seems to be ISO 100 or 50, depending on the scene.

I developed the film towards the end of my C-41 developer, so discarded the chemistry after the slide film was developed. My question to the RFF community is:

Would developing slide film (E6) degrade or damage the C-41 developer? Meaning, would I get unpredictable results with negative film, after I've processed slide film in the developer?

 

[Freakscene]

Colour negative films are optimized for printing and are low in couplers and contrast to give sharp images and remain printable. Color reversal films are rich in couplers and are designed to give high contrast and saturation. Developing E6 films in C41 chemistry gives high contrast saturated images and they are often hard to print or scan. Kodak recommends adding (up to about 2 g/l) citrazinic acid to the C41 developer to moderate the contrast increase.

The chemicals will be ok for C41 after cross processing E6, but the excess of couplers means you have less capacity and get colour crossover sooner. When I worked in a lab that did cross-processing with fairly high volume (which now seems like an aeon ago) we ran a separate line for cross processing and did not use our usual C41 line. We also recommended the now long gone Ektachrome Professional 100 (EPP) for controllability and to avoid insane, unprintable excessive contrast.

Marty

 

[DavidKKHansen]

Hey Marty!

Thanks so much for your input! So I understand that I should expect a few rolls less from my batch of C-41 developer. That's useful to know beforehand, so I don't mess up developments of important films.

Doing C-41 development isn't as hard as some people make it out to be. More care to having exact temperatures, but otherwise seems as straightforward as black & white.

Cheers,
David

 

[sevo]

Thanks so much for your input! So I understand that I should expect a few rolls less from my batch of C-41 developer.

Probably not even that, if you use a un-replenished process - across the maybe three runs per 250ml (one film volume) you will get out of a kit, there won't be any noticeable change, as the developer contains a considerable amount of excess coupler, or you would not get consistent results across several runs with only a small increase in process time. It is only in replenished processes that you'll eventually deplete the couplers, across a much higher number of runs - always putting back slightly less than you remove will eventually let the concentration drop below acceptable levels even if you originally started out with several 100% of excess capacity.

The closest to an official statement would be the Kodak instructions for SO-279 (Vericolor Slide, essentially a cross-processed film used to print slides from negatives). These mandated corrections to the replenishment volume, but explicitly stated that no changes to processing are needed in an unreplenished process.