Saturday, January 14, 2012

PC-Sulfite: A simple developer giving XTOL-quality

Hi folks, I'm a new contributor to this blog. Erik saw my work with ascorbate developers that I reported on, and gave me the honor of contributing here. Here is a useful developer that I discovered, and there are a couple more that I'm working on.

PC-Sulfite gives XTOL-like image-quality with D-23 simplicity. Well, almost as simple as D-23. If your motto is "simple is beautiful", you'll like PC-Sulfite. Here's the 1-liter formula:
Sodium sulfite ................ 90 g
Phenidone ...................... 0.15 g
Ascorbic acid ................. 2.8 g

Target pH = 8.2 (same as XTOL).
Add 15% to XTOL's time as a starting-point.
I use a 1% solution of phenidone in propylene glycol (PG) because phenidone is slow to dissolve in water.
I've tested this formula with Tmax-400 (TMY) and Tri-X (TX) using distilled water at 20C, which covers both conventional grain and T-grain films. I suspect this will work fine on all films, but test first. I've also compared this with test-strips of TMY developed in XTOL, and carefully examining the neg's through 22x loupes, I could scarcely see any difference between them. Same grain and shadow-detail.

Some warnings:
  • When mixing, dissolve the sulfite first, so it'll scavenge the oxygen that dissolved in the water.
  • Use the developer shortly after mixing. PC-Sulfite contains no chelation/sequestration agents, so its shelf-life will probably be short, even if you use distilled water.
  • The chemistry of PC-Sulfite is sufficiently different from XTOL that, for other films, times might vary significantly from the "add 15%" rule above. Test first.
  • I haven't tried diluting it, but the pH of a sample of diluted PC-Sulfite matches that of diluted XTOL, so I'd expect it'll deliver similar results.
An interesting fact: You can be sloppy about measuring the ascorbic acid. For example, boosting the ascorbic acid will help the phenidone, increasing activity, but will also drop the pH, reducing activity. These effects roughly cancel out. My first test had 3.5g ascorbic acid, and the correct time was about the same as this 2.8g version. Both negatives looked about the same. I haven't tried reducing ascorbic below 2.8g, but I'd say that being .1 or .2g off in measurement will have negligible effect.

There's a long thread in (starting here:, and Photo Engineer (PE) encouraged me to remove borate from a formula I'm working on due to environmental restrictions. After doing so, and removing the propylene glycol carrier as well, this is all that was left. It's so simple that I didn't think it could work, but it works well. Here are some test-shots. This is a full-resolution crop developed in XTOL:

And here's a crop developed in PC-Sulfite:

It's hard to see any difference. However, viewing these images on another monitor with a higher gamma makes it clear that PC-Sulfite yields more shadow-detail than XTOL.

As a final test, I walked around my neighborhood taking boring pictures on Tri-X with an Olympus Trip-35. It was a relief to see beautiful frames when I pulled the reel out of the tank. Here's a full-resolution crop of one of my boring pictures:

And the entire 35mm frame:

I hope this simple developer works well for you also.


  1. I wqas kinda wondering if Mark has an update to this, I think he has put in a lot of work on this!

  2. Hi, Mark! Glad to meet you. I have a question: do you think it will give also acceptable results without phenidone? I would like to try it!

    1. Henrik, the whole point of this developer is the two developing agents working together, enhanching each other. So if you omit phenidone you have little or nothing.

      Of course you could try prolinging the developmnent time, but you will NOIT get fine grain and you will loose ISO, which was the point of this developer....

      Make a careful note, you can exchange Phenidone with Hydroquinone, which again negates the whole point of this developer, namely to get rid of highly toxic developing agents, of which Hydroquinone is one of the worst....

      We have an update on this; MyXtol, to be made public shortly with very promising results.

      Also welcome to these pages, I hope we finally will be able to teach you something valuable!