C41 chemicals preservation

narigas2006 · Nov 1, 2007

Hi,

Before I go ahead and mix my chem, I always wait for a reasonable amount of film to develop. I wonder it I have to mix to develop only a few films, is there anyway to preserve mix solutions for longer?

For example, would freezing or keeping cold help?

Many thanks!

Photo Engineer · Nov 1, 2007

Do not freeze.

Chilling helps, as does storage under an inert gas such as nitrogen.

PE

Mike Wilde · Nov 1, 2007

some thoughts on stretching chems life once mixed

For developers:

Start with water (distilled/deionoized) that you have boiled,with the lid on the pot, and then left to cool. This will drive off dissolved gases (oxygen included).

Keep the mixed developer in glass bottles. Plastic lets gases through (although very slowly).

Keep the headspace in the bottle filled with a non-reactive gas ( propane/butane, or nitrogen - look at good wine stores), or use marbles to bring the liquid level up to the top.

Keeping the chems in the fridge between uses will work fine. Freezing may cause some chemicals to crystalize out, and I would not recommend it.

Try to mix just before you have a few batches of film to process. Once the developer has been used, it will not store as long. I home mix c-41 and with the care noted above have got away with 6 weeks between when first used fresh and the final use on non-critical films.

Stop, bleach and fix are not as critical - plastic is likely ok for storage.

Richard Harris · Nov 1, 2007

I try to process one shot in a jobo. With Kodak chemicals I use a minimum of 150 ml per film. If I use the right drum I rarely have to use much more than this to get coverage. My point is get a graduated pipette so that you can accurately measure very small quantities and keep your chemicals unmixed until needed. With an argon shield and decanted in to small bottles my KODAK chemicals will last unmixed for months. You can get argon from a diy welding store in litre bottles.
Richard Harris.

Rob Landry · Nov 11, 2007

Photo Engineer said:
Do not freeze.

PE

Any reasons why not?

Photo Engineer · Nov 11, 2007

The organic chemicals are basic, but are supplied in the original kit as acid salts of the base. This makes them easier to dissolve. Refrigeration runs the risk of these chemicals forming oils and not going back into solution. Freezing just about assures that they oil out.

Once oiled out, there is no longer sufficient sulfite to protect them along with other antioxidants, and therefore the oil oxidzes rapidly to form a tarry scum when you melt it.

PE

Rob Landry · Nov 11, 2007

Does this apply to the concentrates or the working solutions?

I've been freezing my E6 working solutions since 2005 and have never experienced any of this oiling out. I process both Fuji and Kodak emulsions in 35mm and 4x5 and my images are free of any color casts or other defects. I recently sent an identical test roll to my local pro lab to see if my processing could match theirs, well, I have to say that my images were clearer, had no color casts and the colors were more vibrant.

Perhaps C-41 chemistry is different but quite a few of us E6 guys are freezing our chems with good results.

Photo Engineer · Nov 11, 2007

Working solutions of developers. It should not hurt blix, bleach or fix for example, nor should it hurt stabilzer or final rinse solutions.

I would say that you are lucky. I hope that good luck continues.

PE

Rob Landry · Nov 11, 2007

PE,

If you haven't already done so, you should try freezing a small amount of C-41 developer to see what happens. Perhaps it will react differently than the E6 developers but it would be interesting to see.

I don't know if it makes a difference or not, but when thawing my chems, I don't just let them sit out at room temperature, I put them in a sink full of hot water and they thaw in about 20 minutes. When they reach 30-35 degrees C, I roll them across the counter a few times and they all look exactly as they should; first developer is almost clear with just a very, very slight yellow tint and the color developer is a purple-ish color. No precipitates are observed.

Photo Engineer · Nov 11, 2007

Rob;

I have chilled a number of these to close to freezing a number of years ago, and had oil form on the surface. I discussed this with workers at EK and we decided that the diethyl hydroxylamine and CD3 or CD4 were forming an oil on the surface. This rapidly blackened and formed a tar that would not dissolve.

Other manufacturers might use hydroxyl amine itself or other ingredients that do not do this. Also, Kodak has reformulated the kits to use an antifreeze compound in the developers within the last 10 years.

I have never tested E6 chemistry that way as I never worked on reversal film products, but I know that Kodak E6 concentrates for first developer and bleach can sometimes form crystals at room temperature. If this happens, Kodak says that the solution is still usable, as long as you warm gently and dissolve the crystal before use. At the time, these were (and the developer still is) a single solution, but the bleach is now in 2 parts.

All of this may mitigate what I have said. Therefore, I will rephrase my statement to say "Test first and then use what works for you". I usually say that anyhow.

Dumping in an antifreeze in current formulations will affect this situation, but not all mfgrs use an antifreeze. In particular, I point to powder kits. So, your comment may or may not work. I suggest individual tests before the advice I give or that you give is accepted as 'gospel'.

PE

Rob Landry · Nov 11, 2007

Photo Engineer said:
I have chilled a number of these to close to freezing a number of years ago, and had oil form on the surface. I discussed this with workers at EK and we decided that the diethyl hydroxylamine and CD3 or CD4 were forming an oil on the surface. This rapidly blackened and formed a tar that would not dissolve.

PE

Wow, doesn't sound too good. Glad to say I've never experienced anything like this with E6 but perhaps C-41 is different.

My motivation for freezing is not only for longevity but for convenience. Having to find appropriately sized glass bottles and/or use marbles is a hassle. I tried it and it wasn't for me. I'm also not interested in having to get a contract for a cylinder of nitrogen or argon and propane or any other highly flammable gas is just suicide indoors. I love film, but not that much.

Currently, I use a Jobo and their 3010 Expert drum for 4x5 and their 2500 series tanks for 35mm. The 3010 takes 330ml per tank and the 2523 tank takes 270ml. So, after mixing the full 5L kit, I just divide each chem into 333ml sizes, pour into 500ml plastic water bottles and throw 'em in the deep freeze. This gives me 15 sets of chemistry out of the kit. The bottles are CHEAP, readily available when you buy bottled water and allow plenty of room for expansion.

When I want to process, I just pull out a "set", thaw in the sink for 20-25 minutes and dump each chem directly in the Jobo; no mixing or measuring required. For me personally, the worst part of film processing was always mixing the chemistry; it's finicky, sometimes messy and takes quite a bit of time. Besides cleaning the mixing containers and graduates is too much like doing the dishes. Having to do it only once per 5L kit is a godsend.

My processing cost is about $2.15 per 35mm roll and $0.43 per 4x5 sheet. I'm sure I could find ways to make it even cheaper but compared to what the local lab charges, I'm content the way things are now.

Photo Engineer · Nov 11, 2007

Well, Rob, the developers don't contain any antifreeze components as far as I can see. I checked the bottles and my memory was faulty. This was a check of both C41 and RA chemistry on my shelf.

As I always say though. Use what works. My work is probably obsolited by your observations of current developers. I'm just happy that it does work.

I never have put chemistry like that into our home refrigerator though.

Best of luck.

PE

Photo Engineer · Nov 11, 2007

Am I stupid or what?

I owe everyone an apology here.

The work I did now comes to mind more clearly and it was with C22 and EP3, not the present formulas. Those old formulas as well as E4 contained benzyl alcohol and this promotes oil formation at low temperatures.

So, that is why I gave my answer, and I apppear to have been 100% incorrect. My sincerest apologies for the confusion.

Freeze with confidence Rob.

(See what old age does? Too many essential things begin to fail! )

PE

Rob Landry · Nov 11, 2007

Photo Engineer said:
I never have put chemistry like that into our home refrigerator though.

PE

Definitely a good point, especially for those that have children, it's just not worth it.

Myself, I have a dedicated deep-freeze for my chems and film. The girlfriend and I had originally purchased it with the intention of stocking up on food when it came on sale but you know what they say about good intentions.....I also don't have children to worry about thankfully.

Rob Landry · Nov 11, 2007

Photo Engineer said:
Am I stupid or what?

I owe everyone an apology here.

The work I did now comes to mind more clearly and it was with C22 and EP3, not the present formulas. Those old formulas as well as E4 contained benzyl alcohol and this promotes oil formation at low temperatures.

So, that is why I gave my answer, and I apppear to have been 100% incorrect. My sincerest apologies for the confusion.

Freeze with confidence Rob.

(See what old age does? Too many essential things begin to fail! )

PE

Hey no need for apologies, just glad you were able to figure it out. Thanks again for all your help and experience.

Man I find this stuff interesting which is funny because I hated high-school chemistry and failed university chemistry twice. Yeah, I'm not the brightest bulb on the tree.

L Gebhardt · Nov 11, 2007

Rob, are you freezing the Kodak or the Tetenal chemistry? I like your idea as a way to save time.

Rob Landry · Nov 11, 2007

I'm working with the Kodak 5L kit.

C41 chemicals preservation

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