Problem Mixing D-76

[Vlad Soare]

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?

Thank you.

[anikin]

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

[Vlad Soare]

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.

[desertrat]

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.

[Photo Engineer]

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

[PhotoJim]

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.

[NB23]

Try warming the whole solution?

[John Austin]

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

[Vlad Soare]

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.

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.

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.

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

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...

[Bob Carnie]

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

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