Dimezone-S instead of phenidone in Pyrocat-HD?

I have acquired some Dimezone-S which is reputed to be a better-keeping variety of phenidone. I'm interested in knowing if anyone has tried it, and if so any advice about equivalent quantities. Someone on the old pure-silver list suggested that I substitute equivalent molar weights (i.e. multiply the recipe's amount of phenidone by about 1.15). He had also done some tests in a very different developer to compare the two versions and found that this conversion worked for him.

Leaving aside the potential for weighing inaccuracy with comparatively small amounts of this chemical, how critical is the amount of phenidone in Pyrocat-HD?

The reason I'm trying this is because I'm using the metol version of Pyrocat-HD since my first attempt with phenidone didn't work at all well. Maybe that batch of phenidone was bad, since all the other ingredients worked very well in the metol batch that I mixed up. The metol version is great, but a little more speed would always come in handy!

john_s said:

I have acquired some Dimezone-S which is reputed to be a better-keeping variety of phenidone. I'm interested in knowing if anyone has tried it, and if so any advice about equivalent quantities. Someone on the old pure-silver list suggested that I substitute equivalent molar weights (i.e. multiply the recipe's amount of phenidone by about 1.15). He had also done some tests in a very different developer to compare the two versions and found that this conversion worked for him.

Leaving aside the potential for weighing inaccuracy with comparatively small amounts of this chemical, how critical is the amount of phenidone in Pyrocat-HD?

The reason I'm trying this is because I'm using the metol version of Pyrocat-HD since my first attempt with phenidone didn't work at all well. Maybe that batch of phenidone was bad, since all the other ingredients worked very well in the metol batch that I mixed up. The metol version is great, but a little more speed would always come in handy!

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John, I dont know who you got the phenidone from, but you must have had a bad batch. I bought 50 gr of phenidone 3 years ago, I have kept it dry and in a dark place and it is still as good as the day I got it.

As to your question, beats me, why dont you try and tell us how it went.

I have substituted Phenidone 1:1 (in a Suzuki formulation) for Dimezone-S and had good results.

The Phenidone I used is around 30 years old, by the way - no change in activity that I can notice. I keep it dry, sealed amber glass container.

john_s said:

Leaving aside the potential for weighing inaccuracy with comparatively small amounts of this chemical, how critical is the amount of phenidone in Pyrocat-HD?

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The amount of phenidone in the Pyrocat-HD formula is not as critical as one might think. In my own tests I have seen very little difference with amounts ranging from 1.5 g per liter to 2.5 g per liter of Stock Solution A. The minimum amount appears to be about 1.0 g, and the maximum about 3.0. Below 1.0 g there is not as much synergism (= longer development times) and above 3.0 g there is an increase in B+F.

I have no experience with Dimezone-S. However, as others have suggsted, phenidone in powder form lasts a very long time. And once mixed in the Pyrocat-HD stock solution the useful life is at least six months in a partially full bottle. And if you need more shelf life out of the Stock Solution A consider mixing it in propylene glycol instead of water, which should increase its life to years instead of months.

Sandy

Where do you guys get Dimezone-S?

psvensson said:

Where do you guys get Dimezone-S?

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I have never purchased or used it. I use regular phenidone and am quite happy with it.

However: Dead Link Removed
advertises it ( and other photo chemicals) for sale in small quantities:

Dimezone - S 4-Hydroxymethyl-4-Methyl-1-Phenyl-3-Pyrazolidone
DZ00100 100 grams $ 34.64
DZ01001 1 lb $125.79

Very cool, thanks. Didn't know about Tech Chem. Apart from better keeping qualities, I thought one of the advantages of Dimezone was that it dissolves easier in water?

Easier dissolution was one reason I wanted to try it. I'm in Australia, and have found that Sigma-Aldrich, the big chemical company, has stopped listing it. I enquired with an English company which has a local agent. Normally the minimum package size is 25kg (enough for 12500 Litres of Pyrocat-HD stock, enough for 2,500,000 films)

I was lucky to enquire just when one customer was taking delivery of 25kg, and they arranged for me to take 1kg. Who in Australia would want 25kg of it? I don't know, but maybe it's used for colour processing of some type, perhaps reversal.

I'll let you know how it goes.

Incidentally, my failed attempt with phenidone involved my use of a stock solution of phenidone in ethyl alcohol (95% food grade) so maybe something went wrong with the stock. It was only a few days old, though.

john_s said:

Easier dissolution was one reason I wanted to try it. I'm in Australia, and have found that Sigma-Aldrich, the big chemical company, has stopped listing it. I enquired with an English company which has a local agent. Normally the minimum package size is 25kg (enough for 12500 Litres of Pyrocat-HD stock, enough for 2,500,000 films)

I was lucky to enquire just when one customer was taking delivery of 25kg, and they arranged for me to take 1kg. Who in Australia would want 25kg of it? I don't know, but maybe it's used for colour processing of some type, perhaps reversal.

I'll let you know how it goes.

Incidentally, my failed attempt with phenidone involved my use of a stock solution of phenidone in ethyl alcohol (95% food grade) so maybe something went wrong with the stock. It was only a few days old, though.

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Most likely that was your problem, once diluted, even in alcohol, phenidone goes bad pretty quick. BTW, why dont you try Artcraftchemicals in the US? Michael ships to me in Mexico and he always does an excellent job. It might be cheaper even with the shipping than buying 25 Kg. No?

psvensson said:

Very cool, thanks. Didn't know about Tech Chem. Apart from better keeping qualities, I thought one of the advantages of Dimezone was that it dissolves easier in water?

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Suzuki implies that Dimezone-S is easier to dissolve in water than Phenidone. I have no problem dissolving Phenidone in water if I first dissolve it in a small amount of alcohol. This should be done as an integral part of a developer mixing sequence. Pyrocat-HD "A" solution, prepared this way, will last for months.

An alcohol or alcohol/water Phenidone stock solution will start oxidizing almost immediately - with no appreciable color change.

To prepare a stable Phenidone stock solution, dissolve the Phenidone in propylene glycol.

How about dissolving the phenidone in alcohol with salicylic acid, as Ryuji recommends? Anyone tried that?

psvensson said:

How about dissolving the phenidone in alcohol with salicylic acid, as Ryuji recommends? Anyone tried that?

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That Suzuki recommendation was in the context of mixing stable ascorbic acid/phenidone developers.

I have looked through his postings and could not find any references to mixing phenidone/salicylic acid stock solutions.

Here are 2 formulations, based on Suzuki developers, that I modified to produce concentrated TEA stock solutions.


DS–14 Modified, (Neutral Black Tone Paper Developer)

Triethanolamine---------------------------350 ml
Ascorbic Acid------------------------------68 grams
Phenidone ---------------------------------2.3 grams
Triethanolamine to make-----------------500 ml

To make 1 liter of working developer, take 50 ml of DS-14A, add 850ml water, 12 grams sulfite and 30 grams carbonate and mix. Then add water to make 1 liter.

Add 0.2% Benzotriazole as needed to achieve desired tone
---------------------------------------------------------------------------


DS–15 Modified, (Warm Tone Soft Working Paper Developer)

Triethanolamine--------------------------350 ml
Ascorbic Acid------------------------------47 grams
Metol---------------------------------------5.8 grams
Triethanolamine to make----------------500 ml

To make 1 liter of working developer, take 50 ml DS–15A, add 850ml water, 5 grams sulfite, 8 grams carbonate and mix. Then add water to make 1 liter.

Add 2% solution of KBr as needed to achieve desired tone

Tom, on this page, Suzuki says:


So he's talking about Phenidone B or Dimezone, not Phenidone A, but it implies that the salicylic acid is good for more than preserving ascorbate.

psvensson said:

Tom, on this page, Suzuki says:

Phenidone may be substituted for Dimezone S, but the solution should be used soon after mixing. Phenidone B or Dimezone may also be substituted for Dimezone S with no loss of stability, but it is best to dissolve it in alcohol first together with salicylic acid.​

So he's talking about Phenidone B or Dimezone, not Phenidone A, but it implies that the salicylic acid is good for more than preserving ascorbate.

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Yes, that is the same page I'm refering to. The context of that section is the mixing of an ascorbic acid developer.

In another post (I can't find the URL) Suzuki goes into great detail about the the beneficial effects of salicylic acid for the preservation of the ascorbates in ascorbic acid developers.

Suzuki advocates the use of salicylic acid in both his DS-14 (Dimezone-S/Ascorbic acid) and Ds-15 (Metol/Ascorbic acid) developers.

I use Dimezone S in formulation for a T-Max developer clone. There was considerable discussion about this agent versus Phenidone in a series of privately published photo bulletins that ran in the early 1980's, way before Internet communications. It is better than Phenidone in the T-Max formulation, but I doubt it will make much difference in your Pyrocat formula.

Dimezone S is also preferred in E-6 first developer formulae that are MPQ solutions. Here is the note I have in my formulary:

1% Dimezone-S solution with 2% Sod. Sulfite can be used in place of Phenidone base. See D. Neville SuperBulletin #37 for a discussion of the advantages of Dimezone S versus Phenidone. Multiply phenidone by 1.27 to give the Dimezone S substitution amount.