Replenishing diluted developer

[Marco Milazzo]

Let me explain my slightly complicated question:

I like to develop 120 roll film in a tank at ambient (room) temprature when possible. In the warm desert where I live, that CAN mean short development times, risking uneven development. Therefore, I normally use D76 1:1 to lengthen development times.

I want to try replenishment, rather than one-shot developing.

My question: Can I use D76 developer 1:1, and replenish it with D76-R (replenisher), also mixed 1:1? (I would add 2X the amount specified on the package to replenish straight D76).

Is there any reason this wouldn't work?

[Lenny Eiger]

Well, D-76 is not a great developer. I would try Xtol or one of the Pyro type developers.

Replenisher is useful for labs be able to replenish a large tank. If you aren't developing every day then "one-shot" is much more controllable, or more specifically, more repeatable and accurate. That's what most people do. They ignore the replenisher...


Lenny

[Jay DeFehr]

Marco,

Theoretically, you would add 1/2 the amount of D76R, not 2X, but there's no guarantee it would work like stock D76 and D76R. A dilute solution doesn't typically keep as well as a more concentrated one, since there is more water/oxygen to oxidize less developing agent, and less preservative to protect it (as a ratio to the solution volume). The whole system should be much more unstable than the stock system, and more difficult to keep in control. If you MUST process at high temperatures, I suggest you actually test for uneven development, and then assess the risk. There are many high temperature/rapid processes that produce consistent results. I used to use a developer that developed film in about 60-70 seconds, and never suffered uneven development. I would be more worried about inconsistent results trying to use a dilute replenished system than I would be worried about short development times. The best solution is probably to invest in a water chiller, and run your process at recommended temperature. Good luck!

[Bruce Watson]

Is there any reason this wouldn't work?

Maybe. When you dilute, you increase the amount of water, and with it, the amount of dissolved oxygen in that water. That leads to increased oxidation, and therefore decreased shelf life.

This is why Kodak et. al. doesn't recommend storing diluted developer. If you dilute, you should dilute just before using, and discard after using.

That said, you can try it and see if it works for you. Perhaps it will, but if it doesn't you'll have a clue as to why it failed. Maybe.

[ic-racer]

I'd use T-max RS.