Problem Mixing D-76

Hello,

I've been mixing my own D-76 for the past three years, and I've never encountered this problem. Nothing has changed in my workflow. I'm using the same electronic scale (which is properly calibrated), the same chemicals, even the same brand of distilled water.
So, I put approximately 700 ml of warm water (at about 40 to 50 degrees Centigrade) on the magnetic stirrer, add two grams of metol, then wait until it's fully dissolved. Then I start to add the sulfite. At first everything looks right, but after a while the whole solution turns cloudy, and a thin layer of foam appears on its surface. From this point on, any amount of agitation is useless - the solution remains cloudy no matter what I do.
The sulfite is definitely good, there's no doubt about that. It's fresh, and it did work perfectly with my previous batch of D-76.
What's happening? :confused:

Thank you.

Usually it is recommended to add a pinch of sulfite before metol. It scavenges the oxygen.

However, most likely it's the water that has changed. Quality of tap water changes drastically depending on the season. I would try distilled water to eliminate that variable.

EDIT: Oh, sorry. I noticed you used the distilled water. Scratch that suggestion. How about: stop using beer glass as a mixing container

I usually do add a pinch of sulfite before the metol. But no matter if I do this or not, the problem still persists.
I'm using bottled distilled water.
The first half (give or take) of the sulfite seems to dissolve correctly. Then, as I add more, something suddenly starts to go wrong.

I've made a couple of batches of D-76 in the last couple of years, and even using distilled water, both batches were cloudy after mixing. I suspect the borax, which is not photo grade, but a laundry product. After waiting a couple of days, the mixed developer cleared up, leaving a thin, light brown residue on the bottom of the container. I carefully decanted the D-76 into another container before using, so as not to stir up the sediment at the bottom of the storage container. The developer worked fine.

Your Sulfite may be oxidizing and becoming Sulfate which is a lot less soluble. Or, it may be contaminated.

OTOH, maybe there is something in the water even if distilled that may be doing this. Calcium might cause the precipitate to form.

PE

50 C is better than 40 C, although I'm not sure that's your problem. The Kodak instructions recommend about 51 C, if I recall correctly.

Try warming the whole solution?

Get a new bottle of sulphite and try again, this will prove whether or not your sulphite has morphed into something nasty

I have used tap water for my deep tank of D76d since may 1985 with no problems, so try a batch with different water - The D76d is cared for like a dear friend and like me improves with age - Yes, the same tank of dev' since 1985

My replenishment regime is available to anyone who wants it, but it has to be used a lot - Under use is where problems arise

Thank you for your replies.

I've made a couple of batches of D-76 in the last couple of years, and even using distilled water, both batches were cloudy after mixing. I suspect the borax, which is not photo grade, but a laundry product.

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My solution became cloudy long before adding the borax (which, in my case, is photographic grade anyway, at least in theory). I managed to dissolve a little less than half of the sulfite before it clouded up.
The third time I let the developer sit overnight. The next morning a fine layer of white sediment had settled to the bottom, which I filtered out. The developer worked fine. Nevertheless, this shouldn't have happened. My D-76 has always been nice and clear right from the beginning.

OTOH, maybe there is something in the water even if distilled that may be doing this. Calcium might cause the precipitate to form.

Click to expand...

Thanks, Ron. I'm beginning to suspect the water, too, because I've noticed that my assumption was wrong - it wasn't the brand I used before. My wife bought it for me from the supermarket, and it seems she picked up a different brand (not that I would have expected this to make any difference, but who knows...)
What could be there in the water that could precipitate in the presence of sodium sulfite? I'm tempted to rule out calcium compounds, as the water is specifically marketed for all applications where hard water could cause damage. Besides, I did dissolve sodium sulfite in tap water (which in my area is very hard) on various occasions and never had any precipitate. What kind of residual ions can react with sodium sulfite to form precipitates?

50 C is better than 40 C, although I'm not sure that's your problem. The Kodak instructions recommend about 51 C, if I recall correctly.

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Indeed, but that's just to speed things up. Given a magnetic stirrer, D-76 can be mixed at room temperature. I've tried that myself some time ago; it takes slightly longer, that's all. Sodium carbonate is more stubborn, though, so heat is a must for print developers.
Sodium sulfite's solubility at room temperature exceeds the amount needed in D-76 by far.

Get a new bottle of sulphite and try again, this will prove whether or not your sulphite has morphed into something nasty

Click to expand...

I'll have to do that anyway, as this was last supply of sulfite. But I'm positive the culprit wasn't the sulfite. It was reasonably fresh (bought last spring from a reputable company), stored in complete darkness in a tightly closed glass jar. And it did work perfectly until recently. It was definitely good.

The developer seems to work fine after I decant most of the sediment and filter out the rest. So I'm going to use it as it is, and by the time I buy more sulfite I'll revert to my regular brand of water. We'll see what happens next time...

Sodium sulphite going bad is this common or possible, I just purchased 10 kilos of the stuff.

jbaphoto said:

Get a new bottle of sulphite and try again, this will prove whether or not your sulphite has morphed into something nasty

I have used tap water for my deep tank of D76d since may 1985 with no problems, so try a batch with different water - The D76d is cared for like a dear friend and like me improves with age - Yes, the same tank of dev' since 1985

My replenishment regime is available to anyone who wants it, but it has to be used a lot - Under use is where problems arise

Click to expand...

Sulfite can indeed go bad and you end up with Sufate which is less soluble.

Vlad;

DE is made from 2 different kinds of stills and they are cleaned by different methods. Basically, an unclean still can drop scales or particles of Calcium into the distilled water along with iron from the pipes if they corrode. Cleaning must be done with special cleaning compounds which include a sulfonic acid, and if you don't get it clean enough some of the scale gets through the system along with some of the acid.

I am not an expert in this field by any means but I have seen how DW can vary and affect end results. But, I have to say that it is a stretch to include the DW in the possible list of culprits as it would take a very unclean facility to produce such bad DW. It happens, but not commonly.

I have even heard of tap water being sold as DW. Again, another stretch.

Best of luck.

PE

Photo Engineer said:

I have even heard of tap water being sold as DW. Again, another stretch.

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Not as much stretch as you think. You can't always trust the label:

http://www.vegaschatter.com/story/2011/8/2/17325/77878/vegas-travel/Another_Do_Not_Do_in_Vegas_Do_Not_Buy_Water_Bottles_Off_The_Street

http://www.cpaptalk.com/viewtopic/t47317/Fake-Distilled-Water-Sold-in-Canada.html

Photo Engineer said:

Sulfite can indeed go bad and you end up with Sufate which is less soluble.

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Yes, in solution. But can that happen to the dry powder, too?

Yes, dry powder can oxidize depending on keeping conditions.

PE

What are optimum storage of this dry powder??

Photo Engineer said:

Yes, dry powder can oxidize depending on keeping conditions.

PE

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Tightly capped bottle (glass with plastic lid with inner seal of cardboard), at 50% RH or lower and not more than 70 deg F (20C). This will keep 5 years or more.

PE

Thank you Ron... I like you almost as much as I like Ian Grant.

Photo Engineer said:

Tightly capped bottle (glass with plastic lid with inner seal of cardboard), at 50% RH or lower and not more than 70 deg F (20C). This will keep 5 years or more.

PE

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Thanks, I think.

I don't understand this thread. Why would you want to mix your own D76? Why not buy the original Kodak version?

Because I can.
Because chemistry fascinates me, and I really enjoy mixing chemicals.
Because packaged D-76 is not readily available where I live (not at a fair price, anyway).
Take your pick.

Anyway, if I wanted to use a commercial developer instead of making my own I'd have better options than D-76. I use D-76 just because it's so easy and cheap to make at home.

Thanks, Ron. That might explain something that puzzled me a couple of years ago. A friend of mine who had given up film photography gave me one or two pounds of old sodium sulfite. At first glance, it didn't look quite right. Instead of the fine sugary look of sulfite, it had a rather floury appearance. I decided to give it a try anyway. It was very hard to dissolve, and the solution had a muddy look. I suspected that either my friend had somehow mislabeled the bottle and gave me something else, or the sulfite was some impure, technical grade. However, my friend was positive that it was analytical grade sulfite, bought from a reputable company.

I knew it was very old and hadn't been stored in optimal conditions, but I thought that the worst that could happen to sulfite over time would be to turn into a hydrated form.

So, I take it I might have had two pounds of sodium sulfate...

Well, it is probably something like 80/20 Sulfite to Sulfate. It does not go bad with a rush, but rather with a whimper! And during the flip flop results are ambiguous.

PE