Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,924   Posts: 1,556,702   Online: 1166
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 17
  1. #1

    Join Date
    Jan 2007
    Shooter
    35mm Pan
    Posts
    98
    Images
    1

    C41 chemicals preservation

    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!

  2. #2
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,190
    Images
    65
    Do not freeze.

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

    PE

  3. #3
    Mike Wilde's Avatar
    Join Date
    Aug 2006
    Location
    Misissauaga Canada
    Shooter
    Multi Format
    Posts
    2,939
    Images
    29

    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.

  4. #4

    Join Date
    Mar 2007
    Shooter
    Medium Format
    Posts
    123
    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.

  5. #5

    Join Date
    Aug 2006
    Location
    Eastern Canada
    Shooter
    Multi Format
    Posts
    41
    Quote Originally Posted by Photo Engineer View Post
    Do not freeze.

    PE
    Any reasons why not?

  6. #6
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,190
    Images
    65
    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

  7. #7

    Join Date
    Aug 2006
    Location
    Eastern Canada
    Shooter
    Multi Format
    Posts
    41
    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.

  8. #8
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,190
    Images
    65
    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

  9. #9

    Join Date
    Aug 2006
    Location
    Eastern Canada
    Shooter
    Multi Format
    Posts
    41
    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.

  10. #10
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,190
    Images
    65
    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

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin