Effects of Sodium Metabisulfite

[Maine-iac]

Since the rain has been coming down nearly non-stop for the past week up here in New England, my thoughts have naturally turned to doing some developer experimentation. Can't plant my flowers, can't go out making photos, so what else is there to do besides watch all the "season finales," on TV?

As many of you know, I've been using a simple three-ingredient film developer for several years, in one of two variations--(PCM--Phenidone, Vitamin C, Metaborate) or PCC (Phenidone, Vitamin C, Carbonate). PCM for fast T-grained films like Delta 400 and PCC for ACROS or Delta 100.

The other day, I decided to find out what would happen if I added a little Sodium Metabisulfite to the mix.

I began by mixing up the PCC formula:

1 liter water
1/2 tsp (4 g) Vitamin C
1 tsp. carbonate
2.5 ml 1% Phenidone

and added 1/4 tsp. (about 1.3 g) metabisulfite

This gave me a pH of about 9.5, slightly less alkaline than the PCC alone (pH 10).

Decided to try a test roll of Delta 400 at 7:00 at 70F.

The negs came out looking gorgeous. On my second roll, now shot at the speed arrived at on the basis of the first test (200), I further tweaked the development time to 7:30. Haven't printed the test shots yet, but on the light box, they look really nice.

I don't know if the grain is any finer-- still too fine to see with an ordinary loupe, but the negs look to my eyes to be somewhat "crisper," although I realize that means little apart from evidence in final prints. Which I hope to get to tonight or tomorrow since it's still raining.

The interesting thing that I accidentally discovered, however, was that the addition of the metabisulfite appears to have eliminated the residual pink tint in the film base of Delta 400, which has been an intermittent recurring problem. Not only did the developer pour out clear instead of deep purple (dissolved anti-halation coating) at the end of the developing time, but even shortly into the fixing stage, there was little residual pink, and none at all by the time I got to washing.

I'm sure some of you with a much greater knowledge of chemistry than I have will be able to tell me what exactly the metabisulfite is doing in the combination with the other ingredients, and what the effect of the change in pH from 10 to 9.5 is doing. I'd also be interested in any thoughts about the optimum amount of metabisulfite in relation to the rest of the formula, and suggestions for mixing a concentrate. I like what I see so far, and will continue to pursue this in further tests and with real-life subjects once I can get outside again.

Larry

 

[BradS]

It is an interesting question. Unfortunately, one I cannot answer. There maybe a hint to be found in the printed literature concerning the differences between Kodak D-23 and Kodak D-25 however.

 

[Jordan]

Larry,

It seems to me that you are taking your Gainer-like developer and Xtol-izing it to a small extent. I don't think you're activating any new synergistic processes by adding the metabisulfite, but you may be adding a slight "silver solvent" effect and the reduction in pH may be restraining the development process slightly.

I experimented with a similar modification to Pat Gainer's PC-Glycol and PC-TEA and wrote up my results in a "Recipe" article here on APUG: (there was a url link here which no longer exists) Purists may scoff, but I've found myself using it more and more. It gives very consistent and very pleasing results.

 

[psvensson]

At 1.3g per liter, I don't think you're going to see any grain-reducing solvent effect - it's about the same level as many well-known accutance developers like Rodinal and Pyrocat. The sulfite ions may accelerate development a little bit, but you're reducing pH at the same time.

 

[nworth]

Mostly, you brought the pH down to 9.5. You probably also slowed up the development action a bit. I think those two things may account for the better negatives. T-grain films tend to get out of hand at high pH levels, and overdevelopment is always a problem. You may have found just about the right pH. Many recommended soups for these films run at about 8.5 to 9.

 

[Maine-iac]

Jordan, thanks for the link to your article. I've printed it out for reference. And thanks to everyone who've commented.

I've never had a problem with T-grain films being overdeveloped in my three-ingredient formula. I'm not really sure that when I get the negs into the enlarger that I'll be able to notice any real difference between those without the metabisulfite and those with. As I said it was the rainy weather that got me experimenting again just to stave off boredom.

For me, the final print will be the acid test (no pun intended). It might be worth adding the metabisulfite just for eliminating the "residual pink" that sometimes afflicted my Delta 400 negs (though never my ACROS negs).

Larry