Modern Rodinal Substitutes Part II

[Photo Engineer]

Patrick;

I would not think that it would be very stable. I have not seen it for sale recently, but that may have changed.

The Metol equivalent of Rodinal that you were working on is very similar, if not identical to Kodak HDD, a developer sold many years ago and described in Anchell and Troop. It was quite stable.

However, plain Metol in Sulfite and Hydroxide is not. Among other things, it can form Sulfate precipitates which is why I assume you are trying to get the free base of Metol. This would solve the occasional precipitate problem and the relative concentration problems, but not the stability problem. This needs additional ingredients as you have probably already found.

PE

 

[Ian Grant]

Patrick;

The Metol equivalent of Rodinal that you were working on is very similar, if not identical to Kodak HDD, a developer sold many years ago. It was quite stable.

PE

Kodak HDD wasn't stable, like Ilford's Hyfin, and Neofin Blue etc it had to be made up just before use, the very low sulphite level of these developers means they need to be used within an hour of mixing.

So the opposite of Patrick's formula

Crawley noted that Kodak HDD really worked best with Panatomic-X and wasn't really suitable for all films, Tetenal recommended their Windisch formulated HDD for Adox films, and Hyfin was particulary suited to Pan-F and FP3.

Ian

 

[Photo Engineer]

Ian;

A&T state that the stability may have been one of the reasons Kodak HDD was discontinued. I know that. And, that is my point.

A Metol version of Rodinal is potentially doomed to failure through instability regardless of sulfite level. IDK for sure, but it points that way. Metol is much more reactive than pAP as a reducing agent, and if it outstrips sulfite as a reducing agent, then sulfite will not preserve it very well at all.

Kodak HDD is not the "opposite" of Patrick's formula, it is an analog of his formula.

The Kodak HDD design was optimized for older film emulsions as stated by James. It was dropped when emulsions were redesigned rather than continue to produce a marginal product and redesign of the developer was probably considered to be uneconomical. Rodinal was probably redesigned at that time due to the same changes. IDK, but I have mentioned before that changing emulsion types would probably require updated developer formulas.

Not knowing the details, many authors might ascribe things the way Crawley did regarding optimum developer/film combinations. Only insiders might know when an emulsion change would change the response of a product to a given developer.

PE

 

[Alan Johnson]

Metol is said to be sensitive to hydrolysis in alkaline media:
http://books.google.co.uk/books?q=metol+hydrolysis+karlheinz+keller&btnG=Search+Books

 

[Ian Grant]

Ian;
Kodak HDD is not the "opposite" of Patrick's formula, it is an analog of his formula.
PE

Opposite in terms of the amount of sulphite levels, high versus minimal. We're use the word analogous quite differently, of course we're talking about developers using the same components..

In practice those High Definition Developers will still work well with some modern emulsions, the PF sells Crawley's version and European manufacturers make their own equivalents. They've always been a very European thing, it's like Kodinol the Kodak HDD was not available in North America.

Crawley's BJP article Jan 6th 1961 is quite interesting, and he did a lot of work on High Acutance developers. Hee mentions the stability problems.

I'd guess a major reason Ilford & Kodak dropped their HDD's was low sales,the Tetenal Neofin products were better known and sold well. I have some Hyfin but it wasn't stocked by many retailers.

Ian

 

[Photo Engineer]

Metol is said to be sensitive to hydrolysis in alkaline media:
http://books.google.co.uk/books?q=metol+hydrolysis+karlheinz+keller&btnG=Search+Books

That is not immediately obvious looking at the structure, and the odor on decomposition indicates some rather exotic chemistry.

If it were that sensitive, Metol developers would be quite impossible to compound and so the reaction would have to be rather slow at normal pH values. IDK yet. I'm still examining the situation.

PE

 

[gainer]

I seem to remember seeing an acorbate form of Metol, using, I guess. ascorbic acid in place of sulfuric acid on its tail. I am thinking of adding just enough alkali to precipitate the base, then if I'm lucky I will be able to dissolve it again with ascorbic acid after decanting most of the sulfate. Why I would attempt such a thing, IDK. Too much time on my hands, I guess.

 

[Keith Tapscott.]

As things have settled down, it would be nice to see parts 1 and 2 of Modern Rodinal Substitutes merged.

 

[Kirk Keyes]

That is not immediately obvious looking at the structure, and the odor on decomposition indicates some rather exotic chemistry.

I hear is smells like the breath of death! ;^)

That probably would NOT be a big selling point.

 

[Kirk Keyes]

By the way - I once was looking through a "hard to find" standards catalog, and they were offereing "psuedo-corpse scent". It came in 4 versions, on ground and underwater versions - and each of them came in 2 day old and 7 day old...

Here's some: http://www.sigmaaldrich.com/analytical-chromatography/analytical-products.html?TablePage=9620039

 

[Kirk Keyes]

I seem to remember seeing an acorbate form of Metol, using, I guess. ascorbic acid in place of sulfuric acid on its tail.

Pat - what about trying an Amidol analogue of Rodinal? Then you just have to deal with a chloride which should be much more soluble than a sulfate. Or what about a Glycin analogue - you don't have to worry about any salts then. You stil lhave the para-aminophenol backbone structure as in Metol and the para-aminophenol.

 

[Ian Grant]

The problem is Amidol doesn't keep well in solution, nor does Glycin. Ilford worked on a Phenidone - Glcin concentrated developer but in commercial production it had poor shelf life.

Meritol the combination of PPD - Pyrocatechin has been used and had a better shelf life

Ian

 

[gainer]

I'm about to give up on a Metol analog of Rodinal. I could more easily concoct a Metol-C-TEA. I have a compound of Metol and C in glycerin. I call it a compound becuse it seems to be more than a solution. It has 2.5 grams of Metol and 4 grams of ascorbic acid in 100 ml, and took 250 F to get it there. Now I'm out of Metol, but have more p-aminophenol coming tomorrow. I don't like the idea of using KOH, mostly because it's hard to tell what I'm getting when I weigh it because it turns into a puddle while I weigh it. I probably should have made a solution as soon as I opened the container, or else sprung for the money to get it in the solution form. I'm going to see what happens when I use K2CO3 to form the potassium aminophenolate. The CO2 should fizz away for the most part with a little help from heating. We'll see. If that doesn't work, I'll see what I can do with K2CO3 and Ca(OH)2, which will at least make a solution of KOH and a limestone rock I can use as an ornament.

 

[Trask]

Ian -- I was under the impression that glycin didn't keep well in powder form (note Photographers' Formulary's comment on glycin that it has a limited shelf life), but that when it was in solution it would remain stable and active for quite a while, even if it did darken.

 

[Ian Grant]

Glycin caused keeping problems for both Ilford & Paterson developers, but you could use it where shelf life isless important. The importance of Rpdinal is the very long shelf life etc.

Ian

 

[Photo Engineer]

Glycin keeps well in solution, but keeping worsens as pH goes up. It is quite stable in a 2 part developer. Amidol keeps poorly in solution at any pH unless one adds certain stabilzing agents.

PE

 

[Kirk Keyes]

I don't like the idea of using KOH, mostly because it's hard to tell what I'm getting when I weigh it because it turns into a puddle while I weigh it.

You can titrate it with a standard acid. You can make a standard acid by titrating that with a standardized base. Or, you can use potassium acid phthalate (KHP, or potassium hudrogen phthalate) which is a common standard acid and titrate the KOH solution directly with the KHP solid. Use phenolphthalein as the indicator.

That's what all the hip lab cats do, man.

 

[Kirk Keyes]

The importance of Rpdinal is the very long shelf life etc.

I thought it was the result of the development that was important...

 

[Alan Johnson]

Tetenal seem to know how to make metol based developer of high pH that keeps well, see the msds for Neofin Blue in the thread on High Acutance Developer.But they are not likely to spill the beans on how it works.

 

[Ian Grant]

I thought it was the result of the development that was important...

Of course

It's the simplicity of Rodinal combined with the quality of the negatives produced that lead people like Patrick in search of similar developers using different developing agents.

But in a 100+ years it's been copied by many other companies, including Ilford & Kodak but no-one has yet come up with a simple alternative using other developing agents, that keeps well as a single solution concentrate.

This is why Rodinal is so remarkable.

Ian

 

[Photo Engineer]

Ian;

I think HC-110 is rather good as a developer and has good shelf life. I think that some of the higher dilutions of HC-110 have not been fully exploited and may prove to approach Rodinal. I also believe that a Metol based Rodinal, if stable, would be superior to Rodinal.

PE

 

[gainer]

Of course

It's the simplicity of Rodinal combined with the quality of the negatives produced that lead people like Patrick in search of similar developers using different developing agents.

But in a 100+ years it's been copied by many other companies, including Ilford & Kodak but no-one has yet come up with a simple alternative using other developing agents, that keeps well as a single solution concentrate.

This is why Rodinal is so remarkable.

Ian

If I may be allowed to brag a little, PC-TEA is no slouch in that regard. I have not, for some reason, ever made a direct comparison with anything but Acutol, and that was a few years ago.

 

[Ian Grant]

If I may be allowed to brag a little, PC-TEA is no slouch in that regard. I have not, for some reason, ever made a direct comparison with anything but Acutol, and that was a few years ago.

Ian;

I think HC-110 is rather good as a developer and has good shelf life. I think that some of the higher dilutions of HC-110 have not been fully exploited and may prove to approach Rodinal. I also believe that a Metol based Rodinal, if stable, would be superior to Rodinal.

PE

I rather suspect it's swings and roundabouts once these developers are used highly dilute. I know from experience that Ilford PQ Universal and particularly May & Baker (Champion) Suprol give fairly similar results to Rodinal, but with slight speed loss like HC110 or Ilfotec HC.

My own practical experience is that a Pyrocatechin based developer like Pyrocat (any of Sandy King's flavours) or Meritol (PPD/Pyrocatechin) gives the best balance of qualities for my own work. In fact HC1100 was at one point a a Phenidone (or derivative)/Pyrocatechin developer, which is not a co-incidence. But both Kodak & Ilford had to devise exotic cocktails to gain the stability and and exceptional shelf lfe of the super-concentrates etc.

Back in the mid 80's I tested all these developers along with FX-1 & 2 and a few other and non came close to Rodinal's exceptional qualities. The major difference was loss of film speed. Since then Sandy King came up with Pyrocat, which is the first & only developer that I've found to be better than Rodinal.

Patrick I will get around to trying your PC Tea at some stage

Ian

 

[gainer]

You can titrate it with a standard acid. You can make a standard acid by titrating that with a standardized base. Or, you can use potassium acid phthalate (KHP, or potassium hudrogen phthalate) which is a common standard acid and titrate the KOH solution directly with the KHP solid. Use phenolphthalein as the indicator.

That's what all the hip lab cats do, man.

For some odd reason, you made me think of the person who, upon being exposed to a treatise by Thomas Acquinas on "The Divine Simplicity" said "If that's His simplicity, I can't imagine what His complexity would be like."

I would rather spend my time finding out how far I can deviate from "perfection" and still have the essence of Rodinal. I think the essence of Rodinal is a solution of Potassium paraminophenolate with a preservative which might be an ascorbate or a sulfite. It should be easy to prepare it from easily obtainable ingredients.

 

[Photo Engineer]

The ascorbate would contribute to the potency of the developer as it is a developing agent itself. It would decay with time as it also acts as an antioxidant. It would also be affected by the high pH of the KpAP salt and the excess hydroxide present.

Therefore, it may not work.

PE