PC-Sulfite: A simple developer giving XTOL-quality

[albada]

Here's a developer I discovered that gives XTOL-quality with D-23 simplicity. Well, almost as simple as D-23. But before I spend any more time testing this, could somebody tell me if this developer is already known? My searches didn't find this formula. It's so simple that I'm thinking that somebody must have already discovered it. Anyway, 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've only tested this with Tmax-400 (TMY) using distilled water at 20C. I shot all identical frames on a roll, and developed test-strips at 20C using XTOL and PC-Sulfite. Carefully examining the neg's through 22x loupes, I could scarcely see any difference between them. Same grain and shadow-detail.

PC-Sulfite contains no chelation agents and is not buffered, so its shelf-life will probably be short, even if you use distilled water. So use it shortly after mixing.
I use a 1% solution of phenidone in propylene glycol (PG) because phenidone is slow to dissolve in water.
The chemistry of PC-Sulfite is sufficiently different from XTOL that times might vary significantly from the "add 15%" time-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. 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.

In the DS-10 thread (there was a url link here which no longer exists) and (there was a url link here which no longer exists), Photo Engineer (PE) was encouraging me to remove borate from a formula I'm working on due to environmental restrictions, and after doing so, and removing the PG-carrier as well, this is all that was left. It's so simple that I didn't think it could work, but it works great.

Well, did I just re-invent the wheel here? OTOH, if this really is new, then I'll test it some more.

Mark Overton

 

[Christiaan Phleger]

Great! Any idea what the conversion to Dimezone-S would be since I have that on hand....

 

[Ryuji]

Mark, I would strongly recommend against this formula as a practical formula. Despite your observation, formula like this is very intolerant of small errors and performance will be very much variable in practical situations. You are getting into roads that careful chemists avoid.

Borates are very useful buffering agents. There are some known downsides, and I wouldn't use it unless there is a good reason to do so. But any chemical ingredient that has any useful property has good and bad aspects. If you remove the buffering capacity and alkaline agent (borates) from your formula, you must balance with something else. You have to weigh risks and benefits of using each and all ingredients that go into formula and make a rational judgment.

 

[albada]

Despite your observation, formula like this is very intolerant of small errors and performance will be very much variable in practical situations.

Yes, an error of just a few hundreths of a gram of the phenidone will cause a substantial change. But an error of a gram of sulfite will make no perceivable difference, and I've verified robustness in the ascorbic acid. Further testing is needed to gauge sensitivity to type of water (if distilled/DI isn't used), temperature, dilution, and film-type.

And I forgot to mention this recommendation: Dissolve the sulfite first, so it'll scavenge the dissolved oxygen.

Great! Any idea what the conversion to Dimezone-S would be since I have that on hand...

I suggest 0.2 g of dimezone-S, because that's what XTOL uses. Others have changed this to 0.15 g of phenidone in XTOL-like formulae, so 0.2 g dimezone-s should be very close.

Mark Overton

 

[Ryuji]

I've verified robustness in the ascorbic acid.

This formula is not robust against the errors made in the quantity of ascorbic acid. If you don't accept my knowledge on this topic, you should at least run somewhat decent sensitometric test, and report pH of each solution with varying amounts of ascorbic acid used.

 

[albada]

This formula is not robust against the errors made in the quantity of ascorbic acid. If you don't accept my knowledge on this topic, you should at least run somewhat decent sensitometric test, and report pH of each solution with varying amounts of ascorbic acid used.

Yes. Changing the ascorbic acid will change pH. Yet I just re-examined my negatives developed with 3.5g and 2.8g of AA. Their densities are practically identical. But 3.5 vs 2.8 would be a 25% measurement-error. With the virtually the same results. That's robustness.

Here are the pH's I measured:

3.5 g of AA: pH 8.21
2.8 g of AA: pH 8.33
XTOL: 8.37

​

Notice that XTOL is well above 8.20. I thought my meter was reading high, but I did a two-point calibration, and it passes the Borax-test. Methinks that Kodak boosted the pH a little after filing the patent.

Ryuji, when testing DS-10, you noticed that some 100-speed films develop poorly below pH 8.2. I suspect that Kodak observed the same thing late in the game, and boosted pH to give themselves more pH-headroom. Either that or my meter's defective. :confused:

Mark Overton

 

[Christiaan Phleger]

Yes, I think Kodak boosted it when they shifted the packaging way back when it first came out, I never could get a decent neg from Tmax 100. Now its not the case....

 

[analog what is that?]

Just wanted to ask about Phenidone, since more and more esoteric names for this has started to fly:

I have phenidone from Photograpic Formulary
Cat no 10-0870
CAS no 92-43-3

I have done some searching:

- Dimezone (4,4 Dimethyl 1 Phenyl 3 Pyrazolidone)
- Dimezone S (4 HydroxyMethyl 4 Methyl 1 Phenyl 3 Pyrazolidone)


- Phenidone A (1 Phenyl 3 Pyrazolidone)
- Phenidone B (4 Methyl 1 Phenyl Pyrazolidone)

Dimezone S is almost as active as the original
Phenidone but with lower level of fog.



?Name? Dimezone, Phenidone D


4,4-Dimethyl-1-phenyl-3-pyrazolidone
?CAS?

2654-58-2
?Synonyms?

4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDINONE
4,4'-DIMETHYL-1-PHENYL-3-PYRAZOLIDONE
4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDONE
DIMEZONE
DIMEZORE
LABOTEST-BB LT00440816
TIMTEC-BB SBB003657
4,4-dimethyl-1-phenyl-3-pyrazolidinon
4,4-dimethylphenidone
nsc215239
4,4-Dimethyl-1-phenyl-3-pyrozolidinone
4,4-Dimethyl-1-phenyl-3-pyrazolidione
3-Pyrazolidinone, 4,4-dimethyl-1-phenyl-
4,4-Dimethyl-1-phenyl-3-pyrazolidone (Dimezone)
4,4-Dimethyl-1-phenyl-3-pyrazolidon
4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDONE DIMESON
Phenidone D
DIMEZONE (4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDINONE)
dimethyl-phenylpyrazolidine DPP
4,4-Dimethyl-1-phenylpyrazolidin-3-one


Mol-weight.
Phenidone-A : 162.19
Dimezone, or phenidone-D : 190.24
Dimezone-S : 206.24

*****************************

To me it seems obvious it is very important to know what type of Phenidone one has, and adjust the recipes for this, if comparing notes shall serve any meaningful purpose at all.

 

[albada]

Just wanted to ask about Phenidone, since more and more esoteric names for this has started to fly:
I have phenidone from Photograpic Formulary
Cat no 10-0870
CAS no 92-43-3

I just checked the CAS-number on my packet of phenidone from PhotoFormulary. It's the same as yours, 92-43-3. So that's what was used in PC-Sulfite.

Mark Overton

 

[analog what is that?]

Thank you Mark.

I have also another type of Phenidone here, or rather Dimenzione, but don't have the CAS number handy, will get back with that.
Hopefully the others here will also submit their CAS numbers, so we are sure we don't talk past each other and comparing apples with oranges......

PS looking at my notes, could this be the CAS number for Dimezione, and if thats the case, WHAT type Dimenzione exactly :

2654-58-2

 

[oldfaithful58]

PS looking at my notes, could this be the CAS number for Dimezione, and if thats the case, WHAT type Dimenzione exactly :

2654-58-2

http://www.chemblink.com/products/2654-58-2.htm
This suggests its Phenidone D

Dave

 

[analog what is that?]

Name 4,4-Dimethyl-1-phenyl-3-pyrazolidone
Synonyms Phenidone D

Molecular Structure

Molecular Formula C11H14N2O
Molecular Weight 190.24
CAS Registry Number 2654-58-2
EINECS 220-181-1

*****************************

Name Phenidone
Synonyms 1-Phenyl-3-pyrazolidone; 1-Phenyl-3-pyrazolidinone; Graphidone

Molecular Structure

Molecular Formula C9H10N2O
Molecular Weight 162.19
CAS Registry Number 92-43-3
EINECS 202-155-1

 

[Tronds]

Name 4,4-Dimethyl-1-phenyl-3-pyrazolidone
Synonyms Phenidone D

Molecular Structure

Molecular Formula C11H14N2O
Molecular Weight 190.24
CAS Registry Number 2654-58-2
EINECS 220-181-1

*****************************

Name Phenidone
Synonyms 1-Phenyl-3-pyrazolidone; 1-Phenyl-3-pyrazolidinone; Graphidone

Molecular Structure

Molecular Formula C9H10N2O
Molecular Weight 162.19
CAS Registry Number 92-43-3
EINECS 202-155-1

Name Dimezone S
Synonyms 4-Hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone
copyRight
Molecular Structure Dimezone S, 4-Hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone, CAS #: 13047-13-7
Molecular Formula C11H14N2O2
Molecular Weight 206.24
CAS Registry Number 13047-13-7
EINECS 235-920-3

Properties
Melting point 122-126 ºC
Water solubility 7.1 g/L (20 ºC)

 

[Tronds]

Name 4,4-Dimethyl-1-phenyl-3-pyrazolidone
Synonyms Phenidone D

Molecular Structure

Molecular Formula C11H14N2O
Molecular Weight 190.24
CAS Registry Number 2654-58-2
EINECS 220-181-1

*****************************

Name Phenidone
Synonyms 1-Phenyl-3-pyrazolidone; 1-Phenyl-3-pyrazolidinone; Graphidone

Molecular Structure

Molecular Formula C9H10N2O
Molecular Weight 162.19
CAS Registry Number 92-43-3
EINECS 202-155-1

The CAS Registry Number 92-43-3 also gives this information on http://www.chemicalbook.com/CASEN_2654-58-2.htm
?Name?

4,4-Dimethyl-1-phenyl-3-pyrazolidone
?CAS?

2654-58-2
?Synonyms?

4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDINONE
4,4'-DIMETHYL-1-PHENYL-3-PYRAZOLIDONE
4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDONE
DIMEZONE
DIMEZORE
LABOTEST-BB LT00440816
TIMTEC-BB SBB003657
4,4-dimethyl-1-phenyl-3-pyrazolidinon
4,4-dimethylphenidone
nsc215239
4,4-Dimethyl-1-phenyl-3-pyrozolidinone
4,4-Dimethyl-1-phenyl-3-pyrazolidione
3-Pyrazolidinone, 4,4-dimethyl-1-phenyl-
4,4-Dimethyl-1-phenyl-3-pyrazolidone (Dimezone)
4,4-Dimethyl-1-phenyl-3-pyrazolidon
4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDONE DIMESON
Phenidone D
DIMEZONE (4,4-DIMETHYL-1-PHENYL-3-PYRAZOLIDINONE)
dimethyl-phenylpyrazolidine DPP
4,4-Dimethyl-1-phenylpyrazolidin-3-one

Please notice that Phenidone D is also known as Dimezone, the version with out the S-ending.

 

[analog what is that?]

There 3 types of Phenidone (or Dimensione) make a note of the variation in molecular weight, this has a large impact on the formula....
Couple this with possible and expected variations in activity between them, we need to be very careful here....

So now the question is, does the experts chiming in on this thread know of differences between these and has recommendations on what CAS number we should get?

 

[Photo Engineer]

I've stated before that stability in alkali goes up in the series Phenidone, Dimezone, and Dimezone S. The last word is that Dimezone S was the preferred agent and all new Kodak formulas would have used it. All Kodak instant films used it. Dimezone S is about the same in activity as the others. It appears to be less active, but that is partly due to the molecular weight compared to Phenidone.

I think that some scanned examples of films produced by this developer compared to Xtol would be useful.

PE

 

[Ryuji]

Notice that XTOL is well above 8.20. I thought my meter was reading high, but I did a two-point calibration, and it passes the Borax-test. Methinks that Kodak boosted the pH a little after filing the patent.

Ryuji, when testing DS-10, you noticed that some 100-speed films develop poorly below pH 8.2. I suspect that Kodak observed the same thing late in the game, and boosted pH to give themselves more pH-headroom. Either that or my meter's defective. :confused:

As far as I know, Kodak never changed the pH of XTOL. pH of 8.20 and 8.37 would require serious adjustment in development time.

But you are using single junction gel-filled electrode, so I am not sure how trustworthy your measurements are.

 

[Ryuji]

Just wanted to ask about Phenidone, since more and more esoteric names for this has started to fly:

*****************************

To me it seems obvious it is very important to know what type of Phenidone one has, and adjust the recipes for this, if comparing notes shall serve any meaningful purpose at all.

The variants have differences but they are mostly related to solubility (Dimezone is least soluble, Phenidone B and Dimezone S are a bit more soluble, Phenidone A is most soluble) and stability (Phenidone A is least stable in alkaline solution, Phenidone B a bit better; Dimezone and Dimezone S are about the same and better than Phenidone A/B) and there is not much to worry about in terms of adjusting the quantities. If you are preparing developers from powder and for immediate use, Phenidone A or Dimezone S is best. Otherwise, Dimezone S is the only winner.

 

[Ryuji]

Here are the pH's I measured:

3.5 g of AA: pH 8.21
2.8 g of AA: pH 8.33
XTOL: 8.37

​

OP said pH was 8.20 with 2.8g AA. Before that, you were saying below 8.00 in the other thread. Now you are saying 8.33. Are you not worried about these huge discrepancies? Something is wrong in your system.

 

[albada]

OP said pH was 8.20 with 2.8g AA. Before that, you were saying below 8.00 in the other thread. Now you are saying 8.33. Are you not worried about these huge discrepancies? Something is wrong in your system.

Very good! I was waiting for somebody to notice that difference. I recently got a pH meter, and was struggling with reconciling its measurements. Also, the other thread has a different amount of AA.

Anyway, I haven't heard anyone say that they already knew about this formula, so it appears to be new. I'll do more tinkering and testing, but it's lower priority, so results won't come soon.

Mark Overton

 

[albada]

Here are scans of test strips, identically exposed, and developed with XTOL and PC-Sulfite.
The XTOL scan:
And a crop:

And the PC-Sulfite scan:
And a crop:

These images are darkish because I set the white-point as high as possible in the scanner, to clip as little data to white as possible (i.e., maximize the dynamic range). The black-point was set to the left side of the histogram (which was always the same). Gamma was 1.5.
This is part of my camera-collection, lit by the overhead tungsten candelabra. It's hard lighting, which creates plenty of specular reflections to see how the dense part of negatives are doing. Unfortunately, my Coolscan IV ED scanner doesn't have enough dynamic range to cover such specular reflections well (and still show shadow-detail in the neg's), so many reflections clip to white.

In the crops above, PC-Sulfite appears to have slightly less grain than XTOL. That's not true. In 22X loupes, they seem to have the same grain. The scanner's focus has a little variation, and the film isn't held perfectly flat, so grain is defocussed by unpredictable amounts. To get sharp images of grain, I want to photograph negatives in a microscope.

Mark Overton

 

[dynachrome]

I don't know what the advantage of this developer is. You can change the formula and make PC-TEA. This completely eliminates the sulfite and produces a developer with much better keeping qualities. Triethanolamine (TEA) can be heated safely using a water bath. The resulting concentrate, usually used at 1:50, makes a less toxic and versatile working solution.

 

[Tronds]

I don't know what the advantage of this developer is. You can change the formula and make PC-TEA. This completely eliminates the sulfite and produces a developer with much better keeping qualities. Triethanolamine (TEA) can be heated safely using a water bath. The resulting concentrate, usually used at 1:50, makes a less toxic and versatile working solution.

Great for those who can get TEA.
Her in europe, TEA is clos to impossible to get, so we have to resort to other methods of doing this.

 

[Ryuji]

I haven't heard anyone say that they already knew about this formula, so it appears to be new.

I don't know why you didn't see me saying it. It's not new. It's one of many things that are obvious to any chemist (including myself) but scrapped due to obvious shortcomings.

 

[Ryuji]

Here are scans of test strips, identically exposed, and developed with XTOL and PC-Sulfite.
The XTOL scan:
View attachment 43620 And a crop: View attachment 43621

And the PC-Sulfite scan:
View attachment 43618 And a crop: View attachment 43619

These images are darkish because I set the white-point as high as possible in the scanner, to clip as little data to white as possible (i.e., maximize the dynamic range). The black-point was set to the left side of the histogram (which was always the same). Gamma was 1.5.
This is part of my camera-collection, lit by the overhead tungsten candelabra. It's hard lighting, which creates plenty of specular reflections to see how the dense part of negatives are doing. Unfortunately, my Coolscan IV ED scanner doesn't have enough dynamic range to cover such specular reflections well (and still show shadow-detail in the neg's), so many reflections clip to white.

In the crops above, PC-Sulfite appears to have slightly less grain than XTOL. That's not true. In 22X loupes, they seem to have the same grain. The scanner's focus has a little variation, and the film isn't held perfectly flat, so grain is defocussed by unpredictable amounts. To get sharp images of grain, I want to photograph negatives in a microscope.

Between these images, the XTOL negative clearly has more contrast and accutance than your PC-Sulfite. You can't judge a developer by comparing things like this.