mixing half kodak D-76

[JRieke]

This may be a stupid question but I'm new to this and haven't been able to get an answer anywhere.

I picked up a package of Kodak D-76 developer recently. The instructions say to mix it in a full one gallon jug. However, since I doubt that I will use a full gallon before it goes bad, would it be acceptable to mix only half the packet?

What would be the best way to store the leftovers? What is the best way to measure half the powder out? I have a postage scale but I don't know if that is accurate enough to give good results.

Any feedback is appreciated.

Thanks

Jeremiah

 

[Photo Engineer]

Jeremiah;

There is probably a thread every month on this very subject.

Do not ever mix part of a powder chemical kit. They just are not uniform enough.

PE

 

[fschifano]

This has been discussed most recently here about XTOL, if I recall correctly. Anyway, my take on the idea is that it is not a good one for a couple of reasons. First, there is no way to guarantee that you'll get an even distribution of all the components that go into that package of D-76. Measuring out exactly equal portions does not guarantee that you'll have just the right amount of each ingredient in each portion. Second, the dry ingredients are packaged in a hermetically sealed envelope containing an inert gas. Once opened, the contents are exposed to oxygen and moisture and will oxidize. Net result, you save nothing because you'll wind up with a batch of bad chemistry that won't work as expected.

Sorry to bust your idea, but that's the story. The best way to keep D-76 is to mix up the entire volume and then split it up into smaller bottles, each full to the brim. This way the only bottle with an airspace is the one you're working. The completely full ones will last at least 6 months. The partially full ones, at least a month.

I prefer PET or PETE plastic bottles, the kind in which soda pop and bottled water are sold. Glass is arguably the best; but it is expensive, fragile, and potentially dangerous. I have experienced no problems using the PET and PETE bottles. Other types of plastics are not suitable because they are too gas permeable for long term storage.

 

[JRieke]

That was what I needed to know. Thanks for the response! I'll go get a couple half gallon jugs.

 

[fschifano]

Actually, I recommend even smaller bottles. 1L or even 1/2L bottles are even better.

 

[JRieke]

are used soda bottles acceptable then?

 

[Bob-D659]

Yes, they work just fine. PETE plastic isn't very gas permeable, which is why it is used for carbonated drinks, and usually can withstand 75psi of pressure.
Tho the pressure resistance isn't really needed for storing D76 for half a year or so. I also use them for RA-4 colour chemistry as well, and a part full bottle of developer easily lasts two months as you can squeeze all of the air out.

 

[mike c]

Thats realy cool idea,think Snapple ice tea is a pete plastic Bob?.

 

[BobNewYork]

Sorry to hijack, (sorta) but what are the Jobo 1 litre bottles made of, and are they any good for a few months or so of storage?

Bob H

 

[Martin Aislabie]

Sorry to hijack, (sorta) but what are the Jobo 1 litre bottles made of, and are they any good for a few months or so of storage?

Bob H

Jobo translucent bottles are made from HDPE

They will slowly taint with developer and eventually slowly turn a old developer brown in colour (or at least mine have)

However all these things are relative, the amount of gassing and permeability of the plastic bottles is insignificant compared to the amount of oxidation a developer gets when it is poured into a bottle.

To reduce the oxidation of the developer as the storage bottle is filled, I pre-fill the bottles with Tetenal Protectan gas - so any splashing/churning/bubbling as the developer is poured/decanted is done in a developer inert atmosphere rather than an oxygen rich one.

I am not sure the Protectan is available on your side of the pond - but there is probably a suitable alternative

Protectan - http://www.tetenal.com/index_c.htm?AKT=01120010001000500055&L=UK

Martin

 

[BobNewYork]

Thanks Martin. I have used them successfully over many years - but when I read a thread like this I start second-guessing. I'll actually be coming over to visit my family in July so I may try and pick up some Protectan then.

Thanks again.

Bob H

 

[BetterSense]

Snapple juice bottles are glass, and have a nice wide opening too. The tops eventually rust, though.

 

[srs5694]

FWIW, I like glass bottles for developer because I can use a Pump-N-Seal device to create a partial vacuum inside the bottle. (This works well with the glass Snapple bottles that have already been mentioned.) This obviously isn't required if the bottle is filled to the brim, but for partially-filled bottles, it has a noticeable effect on extending developer life.

I've started migrating to plastic for stop baths and fixers; these tend to cause the metal caps on Snapple and similar glass jars to decay rather rapidly.

 

[Alan Johnson]

I seem to be in a minority of one on this topic but I actually did this.
Took my D-76 pack outdoors,poured it into a glass jar,stirred it up well.Used the weight of D-76 I wanted,left the rest in the sealed glass jar for 3 years(what's it going to do,react with nitrogen!!)
After 3 years mixed up the rest, perfect results.

 

[BetterSense]

As to the actual topic of dividing powdered developers, I've done it too. I think the whole notion of misproportioned ingredients is based on FUD. If I was really worried about it, I would have poured it all out and divided it with a credit card several times to ensure statistical uniformity.

Now I use wine boxes that hold a whole gallon, allow extended developer life, and take up much less space than multiple little bottles, so I don't bother mixing up half batches anymore. A gallon of D76 doesn't last me 6mo anyway.

 

[fschifano]

Not FUD. I've had Dektol go bad, which contains the same basic ingredients (metol and hydroquinone) as D-76, albeit in different proportions. The package had developed a small breach which I didn't notice. Needless to say the powder was not stored in an inert environment and it surely was not sealed as well as originally packaged. It had oxidized over time; some of the ingredients having turned dark brown. I can't say how long exactly, but it was less than 1 year. Now, Dektol being Dektol, it still worked since this is very sturdy stuff and print development process can be quite forgiving of poor developers. So no sweat there. If the print doesn't turn out well all you've lost is some time and some paper. But negatives are not reproducible, and I wouldn't want to risk ruining them by skimping on potentially unreliable developer.

 

[Larry.Manuel]

Two ideas: [1] I've stored D-76 in a plastic soda bottle for almost 2 months, it is still active, and not at all discoloured.

[2] In Canada we can buy D-76 powder is smaller bags, too - that make up one liter of full strength solution.

 

[fotch]

FUD or BSTS?

FUD or BSTS? Sort of like saying because you drove without using a seat belt for years you don't think its really needed. Rather than risk ruining negatives or having the developer wasted through mixing error, why not just get some small bottles and fill to the brim. Better safe than sorry.

 

[BetterSense]

Yes, I agree. But I know from experience that you can do it, and it works, and I don't buy any of the arguments about the powders separating funny. This is photography, not rocket science.

 

[Lee L]

Yes, I agree. But I know from experience that you can do it, and it works, and I don't buy any of the arguments about the powders separating funny. This is photography, not rocket science.

"In the space of one hundred and seventy six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over a mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Silurian Period, just a million years ago next November, the Lower Mississippi was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-pole. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."

Mark Twain - Life on the Mississippi

 

[Kirk Keyes]

Yes, I agree. But I know from experience that you can do it, and it works, and I don't buy any of the arguments about the powders separating funny. This is photography, not rocket science.

I see your BetterSense is working fine.

 

[Photo Engineer]

Gunpowder used to be made as "mealed" which was simply a mixture of the 3 ingredients. After shipping in open carts or in burlap bags, they found that it burned unevenly due to the separation of the ingredients during the rough handling of the wagon trains that shipped it to the front.

Later, "corned" powder was invented in which the ingredients were mixed into an even paste and dried and then ground (with great danger) into "corns". This powder was much more dependable as it did not separate out during shipping.

Now, this might seem to be an argument in FAVOR of partial use of a developer package, but consider this.....

Some of the ingredients cannot be mixed together, but are rather "corned" in individual groups which are then mixed into one air-tight package. Therefore the different varieties of "corns" can become separated upon shipment into layers which are not easily redispersed evenly. In addition, they are now exposed to air and moisture.

So, the results at best are uneven and unpredictable.

Don't do it.

PE

 

[BetterSense]

One gets such wholesale returns of conjecture out of such a trifling investment of fact.

The irony is that the "never mix up half a batch or you will suffer total protonic reversal" theory is the conjecture, whereas my "in practice it works fine" theory is based on actual experience.

 

[Paul Verizzo]

As mentioned, this topic comes up every few months. And thus, APUG'ers fall into two camps. One, "Oh my gawd you can't do that because gravity will cease," (the theorists) and the pragmatic, empirical, results oriented. You can easily guess which side I'm on.

I wouldn't divide a powder packet, though, without serious mixing by food blender, paint mixer or something. And ya know what? That's exactly how Kodak made the stuff to start with. Mix a lot and portion out. That one liter packet of dry chems came from maybe hundreds of pounds. If you further divide it, you are only replicating how is was divvied up in the first place.

Another system that gets the theorists in a dither is freezing developers. It works (empirical). Just remove from the freezer a day before using so that the sulfite works its way back into the solution.

"Perfection is the enemy of good enough."

 

[Photo Engineer]

My experience is both from theory and practice Paul. The formulas are compounded more like cement in a large dry powder mixer which gives a constant gentle tumble to the blend so as not to break up the "capsules" which protect the various chemicals from coming into contact. It is also done under an inert atmosphere. Therefore there are two significant differences to your description. A food blender destroys the encapsulation and aerates the mix.

I see we have my advice and Kirk Keyes agreeing. We are both practicing chemists with nearly a half century of experience between us. The best I can say to you is do what works, but remember that this may work even 9 out of 10 times but may only work 1 out of 10. Chances are, you are going to have a "dud" developer in the near future. Have fun with it and I hope you don't ruin some valuable pictures. Please agree to take the responsibilty for your advice as well when people come knocking at your door.

The advice we give is foolproof advice.

PE