How long will D76 last ?

[SteveKarr]

Hi Everyone,
I have a small tank dip & dunk set-up in my dark-bathroom. How long will D76 1:1 stay strong in a 1.5 gallon tank without it's floating lid on? This is the tank with the 2.5 inch x 10 inch top surface of solution. The skinny one.

I don't know how to trust it. I have put only 6 sheets of 810 X-Ray film thru it, but it has been sitting a week or so without a floating lid. ('cuz I don't own one)

Any experience would be helpful...
Thanks!
Steve

[Ari]

The best way to know would be to run a test sheet through, but my experience with D-76, straight and diluted, is that it is very stable even when exposed to air and light.

[Mark Sampson]

Well, Kodak has always said that D-76 1:1 should only be used as a one-shot developer (although I don't know why this should be). At several times in the past, I operated sink lines that used straight D-76, replenished with D-76R by the book, with a floating lid. They were quite stable and reliable, with control strips run regularly. Without replenishment, the developer activity will decline with use, and without a lid, oxidization will take a toll. You should at least cover the developer tank with plastic wrap to keep the air out, and consider replenishment.

[Brian Ellis]

I wouldn't store D76 in working solution form. Maybe that's just superstition, I've never run tests, but I would think that even in a good storage container the developer would inevitably deteriorate over time and it would be difficult to be predictably consistent from one film processing session to the next.

To me as a "serious amateur" photographer the costs of chemicals are so small relative to the total cost of making a photograph (when you count things like travel) that it doesn't make sense to take a chance on using bad or deteriorated developer.

[ki6mf]

The alternative is to get container that you can squeeze the air out of. This will help prolong the life of the developer.

[Heroique]

[...] I have put only 6 sheets of 810 X-Ray film thru it. [...]

Here’s Kodak’s very useful Table which addresses questions about D76 (plus other Kodak chemicals).

It says D-76 1:1, in a 1-Gallon tank, is good for eight 8x10 sheets.

(* Keep in mind, the table doesn’t make any claims for “X-Ray” film, but maybe it’s the same as for the films Kodak does list.)

You say your tank is “1.5 gallons” – so after the 6 sheets you’ve already done, Kodak says you’d still have some mileage left. (Of course, this assumes one session.)

[...] How long will D76 1:1 stay strong in a 1.5 gallon tank without its floating lid on? [...]
[…] it has been sitting a week or so without a floating lid. [...]

Hmm. The table says “NR” (Not Recommended) for the “keeping properties w/o use” of D-76 1:1 working solution in a tank. I presume that means an uncovered one like yours. (And it says merely “24 hours” for the same solution in a tray.)

If your tank w/ "used" solution has already been sitting for a week, I’d say “mix a new batch” before I’d say “experiment” with it. I’ll second Brian Ellis on this one. However, I’d still enjoy hearing about any experimental results! Best, give Kodak a call. I normally talk with friendly people there.

— BTW, can you simply mix a new 1.5-gallon batch?

"How long will D76 last?"

I hope as long as b/w film does. I really like it.

[Drew Wiley]

D76 is infamous for changing its activity over time. There are a couple of ways of
making it predictable. The first way is to mix it fresh every time and use it the same
day. But that means you waste a lot of it. What I prefer to do is never use it the same
day it is mixed, but to divide it into tighly sealed, topped-off glass bottles, and try to
use these between a week and a month after mixing. Jugs with floating lids - no way!
Photog. Formulary sells a tweak on 76 which they claim is buffered to make it more
predictable over time.

[Merg Ross]

D-76 in a diluted form should be used once, and dumped. As noted above, D-76 in a tank with floating lid, and properly replenished, will develop hundreds of sheets of film and last for months with consistent results.

However, as Brian suggests, developer is inexpensive relative to other aspects of silver based photography. Consider D-76 1:1 to be a one-shot developer.

[Mark Sawyer]

A floating lid will minimize oxidation (the developing compounds combining with oxygen in the air), but a different set of hydrolyzation reactions with the water will still occur, though more slowly. The more dilute the mixture, the quicker hydrolyzation will degrade the developer. This happens with every developer I can think of.

[SteveKarr]

Thanks to everyone who helped. ... I was hopin' to not waste chemistry or money, but good advice can be better than $5 in my pocket!

Thanks again,
Steve