Average lifespan for homemade developers

Discussion in '35mm Cameras and Accessories' started by jali, Nov 29, 2011.

  1. jali

    jali Member

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    Does anyone know the average lifespan for homemade developers? Mine's are parodinal and beutler, stored in a refrigerator at 19-20* Celcius.
     
  2. Gerald C Koch

    Gerald C Koch Member

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    First don't store photographic solutions in a refrigerator. Certain components can come out of solution due to the cold and be very difficult to bring back into solution. The only developer I know of where the manufacturer actually recommended such storage is Ethol TEC.

    The lifespan of a developer depends on the nature of the developer and varies widely. Rodinal and HC-110 concentrates last for years. Most developers are good for about 6 months if properly stored. Best to make up an amount that can be used in a reasonable length of time depending on your own usage.
     
  3. analog what is that?

    analog what is that? Member

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    10 - 20 centigrade is not a refrigerator, its living room temperature around here in winter!

    You meant 20 Farenheit?
     
  4. daveandiputra

    daveandiputra Member

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    Definitely not Fahrenheit. Here in Jakarta, a 22°c night is freezing! :smile:
     
  5. jali

    jali Member

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    Noted, Gerald. Thanks.


    For a tropical country, 20 degree celcius is definitely cold :smile: Normal temperature is 32-33 degree celcius.
    Does store the solutions in a hot temperature can cause the solution to expire faster?


    *high-five*
    The refrigerator temperature in Jakarta is as the same as the room temperature in europe I guess :laugh:
     
  6. daveandiputra

    daveandiputra Member

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    Temperature aside, my oldest batch of parodinal is 7 month old when I last use it, after that I gave it to a friend to try. If it's still good than it would be 10 months old.
    Of course there's Jay (zorkikat) in Manila, where the climate is closer to Jakarta, who kept his batch for 5 years and still potent.
     
  7. Rol_Lei Nut

    Rol_Lei Nut Member

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    As several stated, life can vary greatly according to formula, storage temperature, dilution and air contact (or amount of air left in the container), not necessarily in that order.

    Concentrated Rodinal can last years or even decades, a working solution of some developers barely longer than the developing time itself.

    A trick is to keep the film leader and develop it in your developer for the normal time & temp: the emulsion side should be as dark as the back (or very dark, if you happen to have an especially light backing). At least that will show if the developer still has some life in it.
     
  8. Mike Wilde

    Mike Wilde Member

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    if you gravitate to home brew, and want a stable shelf life, I would suggest you research Patrick Gainer's discussions - mostly as old posts on this site - on a product he called PC TEA.

    It used phenidone, acsorbic acid, and an organic solvent (that may be hard to find in parts of the world), Tri Ethyl Amine.
    Because there is no water in the formula until it is diluted, it works quite well at staying stable on the shelf. The TEA acts as the needed alkali.

    I mixed some and found it had the the same activity when it was diluted after 8 months as when working solutions were diuted when it was first fresh.

    Gainer also researched using ethylene glycol as the solvent for the developing agent(s), and mixing this (a solution ) with (b solution) of sodium carbonate (and maybe some sulfite; my notes are not handy as I write this) to provide the alkali at the time that the stock solutions are mixed and diluted to the working solution. This approach allowed long term sotrage out to a couple of years for these developng solutions.

    Another home brew that has a long shelf life is PMK - an a+b stock solutions Pyrogallol and Metol based developer, with sodium metaborate (Kodalk) as the accellerator. It is quite long lasting.
    It takes a long time to work at 20C, and I usually work with it at 24C to keep tank times reasonable. It might work well for you. If find it makes quite nice negs when used at 1a+2b+100 water dilutions. Like all pyro formulas, it stains, so gloves are a good idea. My stock A of this went black and inactive in a half full bottle after two years at mostly 16-20C storage. The B never dies.

    A personal favourite long lived DIY single solution ready to be used in a tank with floating cover or stored in a bottle is one I call 777.
    I have been flogged for calling it this, because it is not the exact same as commercial Harveys 777.

    It works best if you regularly develop films, because it is used in a replnished manner, and likes to be 'fed' at least once a week to aminatina a constant level of developing energy.
    The developing agents are metol, glycin (which is very resistant to aerial oxidation) and polyphenyldiamine (base). The alkali and preservative is sodium sulfite.
    PPD is not the nicest developing agent for skin contact, and since the formula is replenished, wear gloves as well to keep the silver which builds up in the solution from depositing stains that get on you and darken thus staining your hands in a way that is only first visible the next day.

    I have kept tanks of this 777 stuff going and working just fine for periods of over a year, when I am shooting enough to keep it happy and fed films to be developed regularly.
    It too like to be worked at 24C, to keep processing times reasonable.

    I hope this gives you ideas of what can work at elevated temperatures, and allows longer than average shelf lives.
     
  9. Gerald C Koch

    Gerald C Koch Member

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    TEA is triethanolamine which is quite different from triethylamine.

    IMHO. you really can't include replenished developers like 777 in any discussion of longevity since fresh developer is constantly being added.
     
  10. Mike Wilde

    Mike Wilde Member

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    Thanks, Gerald. I am quitely in awe of what all of the real chemists here know.

    I am working to increase my chemistry knowledge all of the time. I am making progress; 8 years ago I could not even spell potassium correctly. As to my poor keyboarding skills, everyone who reads my posts should be used to them by know.

    For Christmas my 12yo is getting 'An Illustrated Guide to Home Chemistry' by Robert B Thompson.
    We had this book out from the library a month ago, and he was quite interested in trying a number of the experiments out.

    I likely have most of the stuff that these experiments need from my DIY darkroom chemistry gear accrued over the last 8 years, as well as trolling auctions for glassware, and getting the surplus chems of a bankrupt biochem research lab.