C-41 developing options with focus on shelf life of chemicals

[bvy]

Don't overthink it. I prepare the starter solution first and put it aside. Then I prepare the five liters of developer in a large bucket according to the instructions. Then I add the starter solution. This gives 6.5 liters of working solution which I decant into 6 one liter bottles. The excess goes into a ~600ml plastic bottle and is used first.

 

[mjork]

I mix the developer (and starter) in a 2 gallon storage tank and keep it right in there. The tank has a floating lid and I also add Tetenal Protectan spray to keep the oxygen away.
When I want to develop film, I just use the built-in spigot of the tank to take out the needed amount... pretty convenient.
This is the tank I'm using: https://www.bhphotovideo.com/c/product/88372-REG/Doran_Plastic_Storage_Tank_2.html

 

[dkonigs]

I just wanted to thank all of you for having this conversation last year. I had very similar concerns as the OP when looking into at-home C-41 processing.

I decided to start with the Fuji X-Press C-41 5L kit (only kit available in the US with separate bleach and fix). When opening it up, I decided to only mix up 1L of all the solutions. I then ran the process on a tank with two 35mm rolls, and it actually came out looking great.

Of course it wasn't until a day or two later that I learned that the developer concentrates don't keep... and that you're really supposed to just mix up the full 5L of everything and cold(ish) store full unused bottles of mixed developer to maximize life. So I'm probably going to mix-and-store the rest soon, and cross my fingers.

When I exhaust this kit (more likely due to expiration than due to usage volume), I'm definitely interested in moving over to the Kodak chemicals. Making heads or tails of what those chemicals are, and what you're supposed to buy, has been quite confusing. So I'm very thankful this thread has clarified all of that, right up to the point of basically giving me a specific shopping list. (And to my surprise, that shopping list is actually cheaper than the Fuji kit, for an equivalent quantity.)

 

[Photo Engineer]

The developing agent keeps best in an acidic medium when an antioxidant is present. This is Sulfite! The unopened bottles are also specially sealed with an inert atmosphere blanket over them when packed. So, as long as the bottles are not opened it has the best keeping. If you do open it, you would need a glove box and Nitrogen to reseal them.

When mixed, another antioxidant takes over. This is HAS (Hydroxyl Amine Sulfate).

Both Sulfite and HAS scavenge Oxygen and prevent deterioration. Both premixed and mixed chemistry can last a long enough time together to get about 2 years life out of them. This would be about 1 year each considering shelf life is unknown before you get the kit. I would trust either as long as they look clear (not cloudy) at room temperature, and are no darker than tea in color with no oil or solids on top. I would check the developer with a tiny piece of 35mm leader before use.

The fixer can also go bad due to oxidation just as regular fixer can. The symptoms of bad fixer are the same as bad B&W fixer.

PE