Properly "cooking" D-76 - can you use a large pot?

[pbromaghin]

No, no, no. You must mix it all to make the stock solution.

Why on earth do I need to do that? The powder keeps just fine.

 

[cliveh]

Because you need to keep the ratio of chemical constituents equal.

 

[pbromaghin]

With careful and accurate measuring they will not vary to any significant degree. This isn't rocket science.

 

[MattKing]

With careful and accurate measuring they will not vary to any significant degree. This isn't rocket science.

The powder isn't homogenous. The different components will settle at different rates, and no amount of shaking will result in them being evenly dispersed.

As a result, the developer you mix up at the beginning will differ from the last batch.

The manufacturers actually add the different components to the pouch separately.

 

[Photo Engineer]

Powdered chemicals, no matter the care used with mixing, have separated into distinct groupings based on size and weight. This is a fact of nature and why when you shake a pan of rocks the large ones come to the surface. It is also the science behind pannnig for gold, well known in CO! And so you must never use part of a powdered kit or you risk having a big problem with variations in results from batch to batch.

I have mixed with shaking and stirring and find little difference, but whisks and blenders entrain too much air.

D76 is best fresh or after about 2 days. The one day in the middle it displays higher activity due to a reaction with the dissolved air, and this is why fresh and after 2 days you get similar and the best results.

PE

 

[Gerald C Koch]

I wouldn't worry about using a stainless steel cooking saucepan to heat distilled water for mixing a developer.

To clarify a bit. Stainless steel does not have to be used for heating the water. However, stainless steel, glass or plastic should be used for the mixing container.

 

[Photo Engineer]

However, too much Copper or Aluminum in the water may cause problems.

Be careful.

PE

 

[baachitraka]

Why not just warm the water till 52°C in water kettle and mix the chemicals in 750ml of warm water in a beaker and fill the remaining with cold water?

 

[Simon R Galley]

Dear All,

Please read PE's reply.... and do as he says.

And :

A ) Do not use an electric mixer

B ) Do not subdivide powder chemistry

C ) Use stainless steel or plastic jugs to mix

Simon ILFORD Photo / HARMAN technology Limited

 

[M Carter]

Unless you're really hung up on D-76… I'd say find a 1-shot liquid developer, like Rodinal, HC-110, etc. Just way easier to deal with.

 

[pbromaghin]

Good lord.

 

[DREW WILEY]

I dunno. How come I've never had a problem with 76? I don't use it routinely anymore, but it was the first developer I tried decades ago,
and I do have a lot of experience with it. A few simple things to know. If your tap water comes out brown and puts you in the hospital the next day, it's probably not the best thing for mixing developer... or if it comes from a pond surrounded by white mineral rings and cattle
skeletons. Guess there are a few ways you can screw this developer up, but it takes some effort.

 

[Ronald Moravec]

Round pot so as to be able to stir.

As things go into solution, the reaction generates heat, so temp is maintained.

 

[cliveh]

Why not just warm the water till 52°C in water kettle and mix the chemicals in 750ml of warm water in a beaker and fill the remaining with cold water?

Exactly.

 

[moodlover]

Why not just warm the water till 52°C in water kettle and mix the chemicals in 750ml of warm water in a beaker and fill the remaining with cold water?

Why 750ml? That's less than 1/4 of a gallon. My understanding is that 3/4 of a gallon (3000ml) of water need to be heated, the powder is then stirred in, then a final 1/4 of water (1000ml) is poured in.

 

[moodlover]

Has anyone tried mixing D-76 with distilled water, then with non-distilled but boiled tap water and find any differences? Also wondering how important it is for the water to be distilled at developing stage (for dilution).

 

[Peltigera]

Why 750ml? That's less than 1/4 of a gallon. My understanding is that 3/4 of a gallon (3000ml) of water need to be heated, the powder is then stirred in, then a final 1/4 of water (1000ml) is poured in.

Because he has a one litre packet of D76, not a gallon one.

 

[Photo Engineer]

Has anyone tried mixing D-76 with distilled water, then with non-distilled but boiled tap water and find any differences? Also wondering how important it is for the water to be distilled at developing stage (for dilution).

See my earlier post on this!

PE

 

[fotch]

Wow, 50 years ago, we just read the instructions on the package and it worked perfect. Now a days, its the internet, lots of weird advise, and confusion. Progress?

 

[moodlover]

If you are mixing the commercial product (ie Kodak package), it should make no meaningful difference whether or not you use tap, boiled tap, or distilled water unless your tap water is extremely bad. The packaged product is designed to work when mixed and/or diluted with a relatively wide range of water types, and contains compounds to deal with things like varying water hardness. I have tried mixing a number of formulas (including D-76) with tap vs store-bought distilled water and found no differences.

Distilled water is fine, but tap water should be fine too. Don't overcomplicate this, and pay no attention to how this guy or that guy does it. There is no need for any fancy gymnastics, and there is plenty of latitude. Simply follow the mixing directions on the package and you will be fine.

Ah okay, very good info thanks! Makes me feel a lot more relaxed, I'm pretty scared of messing up my negatives since I come from the safety of the digital world.

Because he has a one litre packet of D76, not a gallon one.

See my earlier post on this!

PE

Ohh okay, I didn't even know a one-litre packet existed! So I guess I'll multiply your numbers by 3.78!

Wow, 50 years ago, we just read the instructions on the package and it worked perfect. Now a days, its the internet, lots of weird advise, and confusion. Progress?

Haha funny how that goes. I think the internet is a blessing cause the packet doesn't specify what kind of water, what to mix things in, what to avoid etc. For example the packet doesn't say to avoid bronze/aluminum and whatnot.

 

[RobC]

All you need is a kettle of boiling water, a plastic bucket, stirring rod and a cold tap.

And a thermometer

Most of the chemical will disolve quite quickly but there's usually a few grains of something which can be stubborn. I use my stirring rod to crush them in the bottom of my mixing jug, Any grains left don't get decanted into storage bottles.

 

[Photo Engineer]

Well, my post dwelt with the use of DW and tap water in which experiment I found no difference. D76 works with most tap waters world wide. There are some outliers due to excessively hard water or other chemical contaminants.

However, you may enjoy this: https://www.youtube.com/watch?v=l_arrE1jSI8

PE

 

[Pioneer]

I wasn't aware that there were this many ways to fiddle around with mixing D76.

Plastic 5 liter jug, plastic spoon, hot water and thermometer to measure the temp. Once mixed pour it all in the Delta 5 liter jug picked up from BH Photo several years ago. I am a bit of a klutz so I use a plastic funnel for this. Use it up, then mix up another batch. If you don't shoot enough film to use up a one gallon batch just buy the one liter bag.

Thanks all. This has been great fun to read.

 

[pdeeh]

I'm rather hoping that yours is not the last word on mixing D76, Dan.

This is APUG after all, and we really must make the effort to keep things as complicated as possible.

Perhaps we could have a poll on the number of people who have large bronze mixing vessels to hand?

Or better still, some solid densitometry data on films developed in D76 that had been mixed in aluminium vs D76 mixed in polyethylene containers, along with properly presented curves?

 

[DWThomas]

Oy! That video! It's utterly astounding how easy the Internet has made it to fabricate "expertise!" Has that dude read the bag?! (As I recall, there are even little graphics for those who can't read {the language}.) :munch: