I’ve got a huge box of D76 that I want to test before mixing

Like the title says, I have a giant box of powdered D-76, from sometime in the very late 90s or very early 00s. It mixes to a total of 38 liters or 10 US Gal. I have no clue if this stuff works or not, but I want to give it a try anyway! If I wanted to mix up just one liter, what would be the first few steps to getting it done?

link for an image of the box

It is problematic, because it is difficult to ensure homogenous results unless you mix up all ten gallons and then divide the liquid.
Are you willing to accept what results that may differ significantly between the first batch you make and the batch you make with what is left at the end?
To try to ensure as much homogeneity as possible, you will need to mix the entire amount really thoroughly, preferably in a humidity and dust controlled environment, and then weigh it accurately, and then divide it by weight - 1/38 per litre.

As MattKing said, you could get differing results by split mixing. Splitting a powder pack is normally not recommended.

However, it is worth a try. Have a look here about a guy that does exactly that.

https://diyphotography.home.blog/2019/02/20/using-kodak-d-76-to-develop-ilford-photographic-paper/

If you want to develop in a small tank, these measurements may help.

27g of D76 in 500ml gives a mix of 1:1 Mix 27g in 375ml water @ 55C then top up with cold water to 500ml. Use @ 20C

16.5g of D76 in 300ml gives a mix of 1:1 Mix 16.5g in 225ml water @ 55C then top up with cold water to 300ml. Use @ 20C

33g of D76 in 600ml gives a mix of 1:1 Mix 33g in 450ml water @ 55C then top up with cold water to 600ml. Use @ 20C

Let us know how you get on.

foc, thanks for the link. He doesn't mince his words does he? Here's his quote

I highly recommend if you use D-76 routinely that you get it in powder form in a large bag, but then mix it as you need it by measuring from the bag with a scale. I do the same thing with the fixer. It saves on purchase costs, and eliminates the pain of shelf life. It’s also very easy to do, and does give consistent results despite what trolls say on the internet (trust me I was once a chemical engineer).

What he doesn't say if how many times he has used his method with success and how many times it has resulted in less than success.
I'd have thought that if it is really a "by chance" method then less than success should have shown up quite quickly so I might conclude that less than success hasn't occurred or I might conclude that he chooses not to say, lest it undermines his standing as the founder of something new the purpose. It all depends on how I feel about this method viscerally

Equally has less than success not happened because he has only used this method on a few occasions and has been lucky so far?

Frankly I don't know and there is nothing in the article to give me any clues as to what I should conclude. My instinct says that if the bag is big enough and if it is shaken well enough then there is a good chance it will be a consistent enough mix each time to be close enough to the same mix. However instinct or visceral feeling is all I have.

When deciding what is right/ likely to succeed and what is wrong/too risky I suspect we may be more influenced by visceral feeling than we realise.

pentaxuser

Kodak's recommendations (and other mfgers') are conservative because they have to be: if people follow the recommendations and don't get good results they will scream that it's all Kodak's fault and the company should be shut down (after being on Photrio for a few months, you probably know that even when people don't follow the directions they will blame the company).

Although splitting powdered chemicals is not formally recommended, if you just want to know if the developer is alive, physically mixing up the powder and taking a small sample to develop some test film should tell you that.

However, you'll then want to be ready to use the rest of the developer in a reasonable time, because:
- most people who have opened an old but sealed container of developer have found that it works.
- but once you open the bag, the clock is ticking on oxidation of the developing agent.
The powder might last a long time if you seal it back up in an airtight container, but it's hard to predict. It might last longer as powder than as stock diluted solution, but your mileage will almost certainly vary.

I'd want to have a "shaker", something to vibrate the stuff up after sitting all these years. The heavier chemicals are surely on the bottom. But after that, sure, why not? There's a lot of info on mixing up D76 as a one shot developer on the internet, and you could mix up just enough for 1 roll and see.

If the OP is worried about oxidation after opening the big bag, then decant the shaken and rolled and mixed up power into smaller jars with airtight lids. (full to the brim so very little air space)
Then pop a small pack of silica jell into each jar and that should help.
I might try this with my next purchase of D76 3.8L size.
Maybe it's time to live dangerously.

Shaking a powdered mixture will cause the chemicals in the package to settle into layers by density. The mixture was likely completely mixed when put in the can or bag and, if it didn't move at all, it would still be completely mixed. If there was no air in the bag, it would not settle any real amount no matter how much you shake it.

Old Gregg said:

In another thread we are discussing a B&W developer that develops film despite not having any developing agents in it.

Click to expand...

Yes but while not wishing to divert this thread away from its prime purpose of helping the OP with the pros and cons of mixing D76, it is pertinent to add that in the case of your reference, Old Gregg, pictures were shown of development that indicated real success.

I cannot say that the OP in that case was not faking it such that the pictures shown were not from what he said he had done, nor even that they were "crap" but heavily doctored for many hour in PS to give us what we were shown but it just seems unlikely to me. However whether we accept that he, the OP, may have something there that warrants investigation depends on our inner feelings towards inquiry in general and the "art of the possible"

In general I strongly suspect that we human beings are not as open to change in the broadest sense of the word as we like to think we are and this affects our behaviour more than we think. We "rationalise" on inner feelings rather than evidence more frequently than we might realise

pentaxuser

If I had a 10 gallon pack of D76 I'd probably give it a go. Redispersing the chemical components evenly would be a problem. (A miniature cement mixer would be the go. Rotating the powder with a gentle folding and turning action. You may be able to adapt a large Jobo tank with some sort of insert like the Mod54 film holder? Just wild ass suggestions ). I wouldn't try this with a 1 litre or 1 gallon pack.

With the price of commercial developers going through the roof in Australia I'm going to start making my own after I have finished my last 3 x 1 litre packs of D76 plus a couple of boxes of Perceptol and a couple of bags of Xtol. Seriously, at 1+1 dilution it costs me close to $AUD3.00 to develop a film in D76 or Perceptol.

It looks as if a fair summary may be as follows: Mixing a large bag of D76 very thoroughly each time may result in a mixture close enough to the correct ingredients each time to ensure that the D76 will behave as it should. Some risk cannot be denied but what counts is, as I said, how often the mix fails. It is those results in large enough quantities to establish a success rate that we lack and may forever lack

It's a bit like reported failures that individuals have with any film they develop. Said individuals are tempted to conclude that film X is crap. In reality we need a lot more failures of the same exact kind to reach any conclusion. don't we?

pentaxuser

foc said:

If the OP is worried about oxidation after opening the big bag, then decant the shaken and rolled and mixed up power into smaller jars with airtight lids. (full to the brim so very little air space)
Then pop a small pack of silica jell into each jar and that should help.
I might try this with my next purchase of D76 3.8L size.
Maybe it's time to live dangerously.

Click to expand...

I use 1liter StopLossBagsTM and I would not be surprised if they make larger ones. www.StopLossBags.com