Phenidone or Dimezone / ID62 or PQ Universal - same or different?

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pkr1979

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Hi all,

I'm intending to mix up some ID62 (the concentrated stock solution): http://lostlabours.co.uk/photography/formulae/developers/devID62.htm

As far as I can understand this is pretty much Ilford PQ Universal except that PQ uses Dimezone instead of Phenidone... So, I guess my question is if I can expect the same results if using the same dilution, time and temp? Or will I have to expect differences?

Cheers
Peter
 

Lachlan Young

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Dimezone and Dimezone-S have exploitable differences/ advantages over Phenidone in terms of formulation design - but are they going to make realistic differences here? Probably not, and from recall the substitutions may vary slightly from 1:1.
 

john_s

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I use Dimezone-S in phenidone formulas (ID-68 and ID-78 and Pyrocat-HD). I use x1.26 because of the molecular weight difference. All has gone well. But I have to say that I haven't done comparative precise measurements.

I do have two batches of pyrocat-HDC, one with phenidone and one with Dimezone-S and I can't notice a difference. I might do some measurements just out of curiosity.
 
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Lachlan Young

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I do have two batches of pyrocat-HDC, one with phenidone and one with Dimezone-S and I can't notice a difference. I might do some measurements just out of curiosity.

It probably won't make a difference there - in a better designed developer (that isn't staining, understands/ exploits the behaviour of Phenidones (and their variants) and has some solvency) Dimezone-S may deliver a wider range of usability.
 
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n a better designed developer (that isn't staining, understands/ exploits the behaviour of Phenidones (and their variants) and has some solvency) Dimezone-S may deliver a wider range of usability.

Are you talking about developers like Adotech and Spur HRX which use both Phenidone and Dimezone-S?
 

Lachlan Young

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Are you talking about developers like Adotech and Spur HRX which use both Phenidone and Dimezone-S?

No, just about what seem to have been the design principles latterly used by the major manufacturers - which are essentially disclosed/ strongly hinted at in the SPSE handbook and onwards in patents/ papers etc.

Regarding Spur, it isn't particularly clear if they're labelling for everything that might be found in the developer (via in-situ reactions etc) as well as the actual ingredients used. Nevertheless, Adotech IV does offer suggestions that some elements of knowledge about specific phenidone behaviours and its exploitable relationships to suitable electron transfer agents along with other emulsion access knowledge has been put into use.
 

Alan Johnson

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No, just about what seem to have been the design principles latterly used by the major manufacturers - which are essentially disclosed/ strongly hinted at in the SPSE handbook and onwards in patents/ papers etc.
Free to borrow if open A/C:

p927 suggests phenidone:hydroquinone 1:20 at pH 9.
dimezone : hydroquinone 1:40 to 1:100 at pH >10.
 
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Lachlan Young

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Free to borrow if open A/C:

p927 suggests phenidone:hydroquinone 1:20 at pH 9.
dimezone : hydroquinone 1:40 to 1:100 at pH >10.

There's also a bit more complexity - a pH of close to 10 seems optimal for highest edge sharpness in 'high definition' optimised developers of PQ type - which falls off as pH goes higher. Essentially if it's Borax buffered, it's geared to finer granularity, Carbonate/ bicarbonate buffered can deliver higher definition/ development activity for various purposes. In other words, something like Pyrocat is delivering higher definition for quite different reasons than the stain.
 

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Free to borrow if open A/C:

p927 suggests phenidone:hydroquinone 1:20 at pH 9.
dimezone : hydroquinone 1:40 to 1:100 at pH >10.

That's a big difference! And it suggests that adjusting Dimezone-S in place of phenidone at 1.26x for MW difference is probably a complete, irrelevant guess. But based on my results, I'll keep doing it.

Also, the above reference appears to be for Dimezone, not Dimezone-S which I have read from someone's tests is rather different (the S variant needing smaller quantity than plain Dimezone)

Sandy King did write here that phenidone in Pyrocat-HD could be in a range of 1.5g to 2.5g without making an appreciable difference.
 

Lachlan Young

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Sandy King did write here that phenidone in Pyrocat-HD could be in a range of 1.5g to 2.5g without making an appreciable difference.

I'd like to know the methodology used for claiming 'appreciable' difference.

And do bear in mind that there are areas in the SPSE handbook which may be several years behind the 'current' science of the time it was published (for commercial reasons), so do check the citations carefully - the segment on acutance seems to do a rather delicate dance around what KRL was willing to disclose publicly (because the whole industry knew the same thing) and what knowledge they were using in active R&D on C-41, ECN-2, E-6 etc at that time. So you get some statements that may depend on a lot of specific emulsion/ developer interactions that aren't necessarily disclosed fully.
 
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pkr1979

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Im not sure if my question above makes much sense... I ask because I assume if its not enough the developing agent will oxidize and stop working.
 
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Im not sure if my question above makes much sense... I ask because I assume if its not enough the developing agent will oxidize and stop working.

No idea, but interestingly Ilford doesn't recommend PQ Universal for roll film development:

"can be used to dish/tray process ILFORD and some other technical films. It is also suitable for dish/tray developing of general purpose sheet films when a fast working, high contrast developer is needed and a high degree of enlargement is not required. For film processing applications it is diluted either 1+9 (high contrast) or 1+19 (pictorial contrast). PQ UNIVERSAL is not recommended for processing general purpose 35mm and roll film formats."
 

Ian Grant

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In the mid 1980s I tested PQ Universal with FP4 and found at 1+29 the combination gave excellent results in terms of tonal range and fine grain, but with a slight speed loss. May & Baker Suprol was being used in some large processing labs 1+29 was their recommended dilution, there was a very detailed guide for it's use.

It's only since the switch to Dimezone that Ilford added that it's not recommended for 35mm and roll films.

Ian
 

MattKing

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In my experience, a lot of Ilford materials frequently use "not recommended" when they mean something like "there are better choices" or "not needed" rather than "one should not".
I could be wrong, but I think it is a UK thing :smile:.
 
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pkr1979

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In the mid 1980s I tested PQ Universal with FP4 and found at 1+29 the combination gave excellent results in terms of tonal range and fine grain, but with a slight speed loss. May & Baker Suprol was being used in some large processing labs 1+29 was their recommended dilution, there was a very detailed guide for it's use.

It's only since the switch to Dimezone that Ilford added that it's not recommended for 35mm and roll films.

Ian

@Ian Grant , do you have any idea how different todays Ilford PQ Universal is from concentrated ID-62 (http://lostlabours.co.uk/photography/formulae/developers/devID62.htm) in character and strength?
 

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It's only since the switch to Dimezone that Ilford added that it's not recommended for 35mm and roll films.

I'd be less than surprised if the tech data revision was largely intended to reduce lengthy technical/ customer support queries/ correspondence from the unwary but then growing 'Advanced Amateur' sector, tripped up by potential shadow speed/ granularity differences from what they might expect. PQU is capable of pretty extreme sharpness with Delta 100.
 

Alan Johnson

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When Crawley formulated a developer for T-max and Delta films he used a P:Q ratio of 1:10
So the SPSE figure of 1:20 may be of its time.
 

Lachlan Young

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When Crawley formulated a developer for T-max and Delta films he used a P:Q ratio of 1:10
So the SPSE figure of 1:20 may be of its time.

I'd suggest that the inverse is true. The proposition you need to start from is that Crawley was generally 10-25 years behind the major manufacturers.
 

Alan Johnson

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I'd suggest that the inverse is true. The proposition you need to start from is that Crawley was generally 10-25 years behind the major manufacturers.

That is rather an original opinion, not sure about that.
For instance if you look at today's derivative of FX-37 type, the phenidone has been replaced by metol but assuming 10:1 weight ratio of activity the Phenidone equivalent : Hydroquinone ratio is still 1:10
 

Ian Grant

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That is rather an original opinion, not sure about that.

I was taken out for a business lunch in Alderley Edge back in the early 1980s by two senior Ilford Sales Managers, we were joined by the head of research. Crawley's name came up in conversation. The research chemist recounted stories of mixing Paterson chemistry in his early days at Ilford, for some years they produced all Paterson's chemistry.

They couldn't get everything in the fixer concentrate to dissolve when they made the first batch, so Crawley added something to aid solubility, the Ilford chemist said it remained being made like that, but in fact he said Crawley should have reduced the level of one of the components which would solve the issue and be cheaper to produce. Another comment was Crawley's use of 3 developing agents in some of his Paterson developers, which he said was unnecessary.

I'd with Lachlan, although perhaps put it differently and say his chemistry was not in the same league as the major manufacturers, or smaller suppliers like Johnsons and M&B. That was definitely the impression I got from Ilford people I was talking to.

Ian
 
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