Suggestion for Kodak C41 kit

Kilgallb · Mar 20, 2025

I bought a 2.5 litre version of the Kodak C41 kit and mixed up half. The developer concentrate when open is listed as good for 12 weeks, but the other chemicals are good for 24 weeks when opened.

This means I have to hold off developing until I gather enough C41 film sheets and use up everything in 12 weeks.

My suggestion is to package the 2.5 litre kit into 2 separate bottles of the developer chemical concentrates. That way I can use half up over 12 weeks, and the other half over the remaining 12 weeks.

Has anyone tried using the developer past 12 weeks?

koraks · Mar 21, 2025

I use Fuji instead of Kodak, but generally mix everything all at once and then store the working strength developer in glass bottles with a tight-fitting cap. This way it stays fine for well over a year.

loccdor · Mar 21, 2025

I often wonder how the manufacturers come up with the mixed-shelf-life figures. It would be good to know their exact reasoning because some of the chemicals have such a longer life if a few common sense guidelines are followed.

Kilgallb · Mar 21, 2025

I have few colour sheets I know are not right so this weekend I am going to see if the remaining concentrate still works. If they do I will develop the rest. (8 sheets)

Klaus Mähring · Mar 29, 2025

I freeze that part of developer concentrate (the one that goes brownish too quickly). Works well for me.
In my experience Kodak C41 works well far beyond the official shelf-life. Bleach and Fix are ok for months, but I make sure to test them before developing critical negs.
Make sure to airate (stir vigorously) the bleach if it has been sitting for a while.

Kilgallb · Mar 31, 2025

orp said:
I freeze that part of developer concentrate (the one that goes brownish too quickly). Works well for me.
In my experience Kodak C41 works well far beyond the official shelf-life. Bleach and Fix are ok for months, but I make sure to test them before developing critical negs.
Make sure to airate (stir vigorously) the bleach if it has been sitting for a while.

Thanks for the advice.

mshchem · Mar 31, 2025

This is true for any C-41 chemistry. It was like this forever. Any C-41 developer will work with any C-41 process. The other bathes may vary but the developer is developer.

Like @koraks suggests the unused working solution stored in full (absolutely full) bottles keeps a long time.

Glass bottles with a Poly Seal cap ( phenolic cap with a HDPE conical liner) will keep indefinitely at 20°C.

Bleach is eternal if you replenish just enough to account for loss.

Fixer not so much, any rapid fixer (film strength) will work for C-41.

Kilgallb · Apr 5, 2025

I developed 8 sheets of 4x5 as one shot. My C41 kit is now 5 months old (20 weeks) since opening the stock solutions.

All negatives processed normally.

mshchem · Apr 5, 2025

Kilgallb said:
I developed 8 sheets of 4x5 as one shot. My C41 kit is now 5 months old (20 weeks) since opening the stock solutions.

All negatives processed normally.

Excellent!

Suggestion for Kodak C41 kit

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