Long, very long, lasting C-41 chemicals

I have been able to keep my C-41 working solutions to last for more than a year, almost 2 years. I thought I should share this method with everyone here. I hope this will encourage more people to develop their own color films which will lead to more consumption of C-41 films and as a result it helps film manufacturers (Kodak and Fuji) to make more due to the long lasting consumption in the market.

The benefit of being able to keep the C-41 chemicals for a very long time is mainly so that one can buy the chemicals in larger packages to achieve a much lower cost per unit of the chemicals without fearing that the chemicals will deteriorate and become unusable before they are used.

I am sure a lot of experts in this forum know the fact that the only chemical in a C-41 process that will go bad fairly quickly due to oxidation is the part C of the color developer. Everything else (Part A, B of developer, Bleach,Fix and Final Rinse) mixed or in concentrate will last just about forever. They do last for years to me and they don't seem to go bad any time soon. A unopened developer Part C will last 1 - 2 years but once opened it will oxidize in 2 -3 months even unused and tightly capped in the bottle. A mixed working developer solution will last only 2 -3 weeks.

This method is really a very simple one with a small extra cost. Just buy some CD-4 (Kodak color developer agent #4) in powder form available from Photographers Formulary. I do not know where else sells it so if anyone knows any other places please share them with us here.

I have quite a few expired C-41RA developer replenisher packages, each contains 4 sets of Part A, B and C to make 10 liters of C-41RA developer replenisher with each set, 40 liters total. All my Part C bottles have gone bad and are unusable. I simply mix the Part A and B per the mixing instruction but leave the Part C out (discarded). This is an incomplete C-41RA developer replenisher and It will last for years even mixed.

Before I use it I then mix this incomplete developer replenisher with C-41RA starter per the mixing instruction to make my incomplete C-41RA developer replenisher solution (still no Part C in it). I then add 5 grams of the CD-4 powder per liter of this incomplete developer solution to produce my C-41RA developer working solution. I only make one liter at a time so it will be completely used in a week or so. There is never any waste of it since it is completely used in a week.

As a result I am not only able to develop C-41 films that yields beautiful negatives I have been able to reuse it (with some replenisher added to top up the lost portion due to rotary processing by my Jobo processor). I have been able to reuse it 3 - 4 times with no or very small lost of quality. The CD-4 powder when buying in bulk will cost about $1.50 per 5 grams. I am sure it can be cheaper still when buying larger bulk each time. The greatest benefit is I no longer worry about my developer going bad any more. I can buy any large bulk developer packages and never worry that I will not be able to use all of it before it goes bad. I will use the Part C until it eventually goes bad then switch to use CD-4 powder. Cost of the developer are way down, despite that I have to buy large packages each time but they will last for years before I have to buy again. The bleach is not very cheap but it will last forever unused even opened. I buy it in large containers (5 liter bottle) and never waste any of it. All other chemicals are fairly cheap and also long lasting.

Well, there is one problem that I was once told. I also need to add something else in addition to the CD-4 powder. I have not seen any problems without it but I agree that there is another ingredient in the Part C that was discarded. Maybe because I am using C-41RA replenisher to begin with so it already has that missing ingredient in it. Perhaps I don't really need to add it. If so then I will just stick with developer replenisher always. Large developer packages are always sold in replenisher form any way. Just remember to buy some starter, which is cheap, too.

Hope this is useful info for everyone. Any comments/suggestions are welcome. Thanks.

Well done!
Though some kits have that type of shelve life with no needed additions or modifications.
We are testing our kit at 3 months intervals, of open bottles, and so far are at 12 months. with the 15 month trial coming up shortly, and i have no doubt that the range of 18-24 months is not out of the question with this material.

I start with and keep liquid mixtures 'forever' (years and years) without any problem whatsoever. Read this and you will heed this:

Mix as per directions. I use Kodak Flexicolor, which is all liquid concentrates. Use PET plastic bottles (soda, Gatorade, almost all juices, etc) and fill them to the very rim. Cap securely. You could also use glass bottles and for small amounts of liquid I use either this or 50ml plastic liquor bottles.

You can even store the concentrates in these bottles if you do not wish to mix everything at once. Just be absolutely certain to fill to the rim, ESPECIALLY the "B" and "C" components of the Flexicolor chemicals. ("C is VERY easily ruined with oxydation.)

For BLIX I use a combination of film strength fixer plus potassium ferricyanide solution (1g PF in WTM 50ml). Just before use, mix one part film fixer (fresh) with one part PF solution. Make certain to stop thoroughly before blixing. - David Lyga

Something along the lines of the OP’s technique has been discussed before here. Personally I have used the technique of using 5 grams per liter of CD-4 to salvage C-41 developer I got from the lab I work at when part C went bad, and it works well. But I never tried mixing parts A and B and leaving out C and adding CD-4 when needed. It sounds like something worth trying. I have always just mixed everything at once and stored in glass jars filled to the top, with great longevity. All good ways to maximize usefulness of C-41 chemistry.

David Lyga said:

I start with and keep liquid mixtures 'forever' (years and years) without any problem whatsoever. Read this and you will heed this:

Mix as per directions. I use Kodak Flexicolor, which is all liquid concentrates. Use PET plastic bottles (soda, Gatorade, almost all juices, etc) and fill them to the very rim. Cap securely. You could also use glass bottles and for small amounts of liquid I use either this or 50ml plastic liquor bottles.

You can even store the concentrates in these bottles if you do not wish to mix everything at once. Just be absolutely certain to fill to the rim, ESPECIALLY the "B" and "C" components of the Flexicolor chemicals. ("C is VERY easily ruined with oxydation.)

For BLIX I use a combination of film strength fixer plus potassium ferricyanide solution (1g PF in WTM 50ml). Just before use, mix one part film fixer (fresh) with one part PF solution. Make certain to stop thoroughly before blixing. - David Lyga

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Thanks for commenting, David. Keep in mind that most PET (HDPE or LDPE) bottles are not oxygenproof. Kodak uses glass bottles for the Part C for this reason I believe. Everything else in a C-41 chemical kit will last a very long time (years) if not forever. Most people are forced to buy small C-41 kits because of the short lived Part C issue. But small kits are far more expensive. As a result some people simply shy away from processing at home and are forced to accept mediocre commercial processing.

I am able to purchase developer packages that are primarily for commercial labs that are far cheaper per unit volume of the developer. The Part C bottles will go bad but I don't care. I simply use powder CD-4 instead. I am very happy that I no longer worry about my developer going bad. I am able to use up to the last drop of it no matter how long it takes me to finish up all the developer from the package.

Can't wait to hear from PE, wondering of this technique can be applied to E-6 as well...

Here's an option you might want to try to eliminate oxidation in partially filled bottles. I came across a "Swissmar Epivac" system at a yard sale. It consists of a small hand-operated vacuum pump and special black rubber stoppers. You simply insert a stopper in a glass pop/soda bottle and then start the vacuum creation with the pump. There is a small "wick-like" stem that sticks up in the center of the rubber stopper. To release the vacuum you just push this wick-like stem to the side - you'll here the air rush in. I bought a dozen extra stoppers thru Amazon. Test the stoppers beforehand to make sure you don't get a dud. I haven't been able to make use of mine yet but I would think they should work - they seem to hold vacuum very well.

mtjade2007:

You know, I cannot definitively state whether PET is fully oxygen proof. But I will say this: if filled to the very rim, you need not worry. At least I don't after having this stuff stored, diluted, for literally YEARS. That has to mean something. It is interesting to discuss this and it comes up rather often. All I can do is relate my experiences to all. Yes, that part C is a very difficult liquid to keep good, but even that works with the PET in my experience.

An interesting note: the PET has a strange quirk though. I have noticed that after maybe one year of unpoened storage there is SLIGHTLY less in the bottle. It is as if there has been slight evaporation!!! I am talking about only, perhaps, 2% of the entire liquid, but it leaves a slight gap in the bottle. HOWEVER, that gap is NOT filled with oxygen. ONLY IF YOU OPEN that bottle do you then have to insert marbles in order to displace that new oxygen. - David Lyga

I keep all of my working solutions for upwards of a year. When I bottle them, I bottle them warm to keep as much oxygen out of them as possible. Then put them in plastic beer bottles from the brew shop. I squeeze the bottle to get my solution up to the very top and cap it. Once the solution cools down and condenses, it creates a vacuum seal as well.

WayneStevenson said:

I keep all of my working solutions for upwards of a year. When I bottle them, I bottle them warm to keep as much oxygen out of them as possible. Then put them in plastic beer bottles from the brew shop. I squeeze the bottle to get my solution up to the very top and cap it. Once the solution cools down and condenses, it creates a vacuum seal as well.

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That's a good plan, hmm perhaps chemistry "canning" is an option... Those ball jars are cheap!

The developer package I deal with contains 4 set of Part A, B and C. Each set is for making 10 liters of C-41RA replenisher. Each time I mix a set of the chemicals to make 10 liters of it. I basically store that much of liquid in 3 gallon sized bottles so the 3rd bottle is always partially filled. Along the way of using the developer replenisher there is no way I can always keep the bottles full. It is a hassle to divide the liquid into smaller bottles so that I could fill each of them full of it with no air in the bottles. Even if I could do that there would be a constant worry in mind that the liquid might not last long and by the time I get to use them only to find the juice has turned brownish.

The availability of the CD-4 in powder form I am enabled to find and buy the largest and much cheaper (per unit of volume) developer package. I store the mixed incomplete C-41RA replenisher (Part C excluded) in gallon sized bottles. I never need to worry about if the bottles are full or not. It will last for years. I pour as much (or as little) as I need any time each time to use it. All I need to do is to add the starter per the instruction from Kodak and the CD-4 powder to it. My cost of processing per roll of films is way down and there is so much more fun to shoot films now knowing that I will get quality negatives always. By the way I own a Jobo ATL-2300.

mtjade2007 Thanks for the idea!

Now if I can only get someone to mail me some CD-4!

I am quite surprised to hear that CD-4 concentrate goes bad so quickly. Others have reported (there was a url link here which no longer exists), with lots of film processed in that time. What also surprises me is that nobody has mentioned protective gas as a way to keep oxygen sensitive liquids for a long time. People have successfully used nitrogen, butane or lighter fuels, and for those who do not want to mess with these, there is Tetenal Protectan in a convenient spray can for the same purpose.

Here is a web page that shows a plastic comparison chart in which the transmission rate of oxygen, moisture, CO2, etc. through the plastic can be compared. PET is much better than HDPE int erms of oxygen transmission rate but HDPE is better in moisture transmission. It seems HDPE bottles are not as good as PET bottles in storing developer. However, most plastic bottles sold for photochemical storage are HDPE bottles. I think coke bottles are PET because they are as transparent as glass. I have heard that JOBO bottles are very oxygen proof despite they are HDPE bottles.

http://www.alphap.com/basics/compare.html

This method can work, but the sulfite level will be quite a bit off, as a large portion of sulfite is in the developing agent concentrate. Since sulfite helps control color purity in color developers, you can get contaminated colors.

It can also reduce sharpness and increase contrast.

PE

If the relevant CD part indeed contains CD-4 and Sulfite only (and the MSDS suggests this, too), one could look at a C41 recipe to find the proper quantities, e.g. (there was a url link here which no longer exists). This would indicate somewhere between 5 and 5.5 g/l CD-4 and 3-4 g/l Sodium Sulfite.

However, C41 CD concentrates don't contain Sodium Sulfite, they contain Sodium Metabisulfite to keep pH low. Based on molar weight, you'd need only 0.75 times the amount of Sodium Metabisulfite, which means a proper substitute for that CD component would add 5.3 g/l CD-4 and 2.64 g/l Sodium Metabisulfite.

Actually, the CD4 concentrate is an adduct of Sulfur Dioxide gas and CD4 (an acid and a base) which together act as two ingredients in the mixed developer and adjust the pH. This method is also used in making HC110 where HBr and SO2 are bubbled through the TEA to make the adducts which then form the Bromide restrainer and SO3 preservative in the mixed developer.

PE

Thanks for the comments from PE and Rudeofus.

I just looked at a Part C bottle of my Kodak C-41RA developer replenisher. It says it contains CD-4 and sodium bisulfite. Sodium bisulfite is very cheap and is available from Photographers Formulary too. So can I substitute Part C (it's gone bad anyway) with 5 grams of CD-4 and 3 - 4 grams of sodium bisulfite per liter?

I tried 5 grams of CD-4 and no sodium bisulfite. I knew the Part C has something else (now I know it is sodium bisulfite) in it. But the negatives came out OK to me. I even reused the developer 3 more times with no problems.

I am not a person with chemistry background. Substituting Part C with CD-4 and sodium bisulfate is simple to me. But if it has to be more complex than that such as dealing with PH adjustment, etc. It would be a dean end to me.

mtjade2007, the Sulfite/Bisulfite doesn't work so much as an oxygen scavenger and developer protector. It reacts with oxidized developer and therefore does two things: first, it prevents an oily precipitate if the CD-4 in the concentrate becomes oxidized from storage. Secondly, it competes with the color couplers of your film for oxidized CD-4, which means it lowers contrast. Obviously you won't see the oily precipitate if you mix your dev with fresh CD-4, but I've seen it with older CD-4 powder.

If you don't enlarge your negatives optically but scan them, the scanner software will hide most developments problems, so you may not see that your negs are off.

The ingredients on my Flexicolor part C lists bisulfite, but no sulfite. When I substitute CD-4 for part C I don't add any bisulfite, print RA-4, and get good gray scales, contrast and skin tones that compare well with Flexicolor. Therefore the lack of bisulfite apparently has no great affect. At least none that is noticable to me.

If it works, use it!

PE

It seems to work for me, but as we say, YMMV!

Photo Engineer said:

If it works, use it!

PE

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Thanks, PE.

I really want to do it right, not just feel that it works. I will experiment more next time by adding sodium bisulfite. It is a cheap chemical and easy to get. If it makes a difference I will report back here. Before that happens Can you tell me if it makes any sense by adding a few grams per liter of sodium bisulfite. Kodak probably does not get it in the Part C concentrate that way. But I can only do it the easy way. Basically I will discard my Part C bottle and substitute it with CD-4 powder and sodium bisulfate.

mtjade2007 said:

Thanks, PE.

I really want to do it right, not just feel that it works. I will experiment more next time by adding sodium bisulfite. It is a cheap chemical and easy to get. If it makes a difference I will report back here. Before that happens Can you tell me if it makes any sense by adding a few grams per liter of sodium bisulfite. Kodak probably does not get it in the Part C concentrate that way. But I can only do it the easy way. Basically I will discard my Part C bottle and substitute it with CD-4 powder and sodium bisulfate.

Click to expand...

Is there a way to adjust this technique for the 3 bath JOBO kit?

I'm about to do a run of C-41 with that kit. I don't have it on hand but I don't recall having an A,B, and C packet... I could be wrong of course.