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

Alan Johnson

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I agree with the wise words of Ian Grant:

Ilford Universal Film Developer

Hi all, In late 1994 I started developing my own film in my apartment kitchen. I went to B&H to buy some D-76 and the salesman suggested, as I was just starting out, that I use a liquid developer. He recommended Ilford Universal Film Developer. I used it for a couple of years, and was...
www.photrio.com
The OP is better off using a dedicated film developer [than ID62]
 

Ian Grant

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You have to see the context of the OP's question with regard to previous posts, and realise Ilford recommend ID-62/PQ Universal for Reversal processing.

One comment I've seen others post online, and I've experienced personally, is when Ilford PQ liquid developers switched from Phenidone to Dimezone they have a shorter shelf life particularly once opened.

There's a myth that Phenidone doesn't keep well, but my 1961 Ilford Phenidone works as well (OK last used two years ago) as my fresh Phenidone. Also, it appears that in PQ developers substituting Phenidone with Dimezone doesn't give quite as fine grain.

This comes back to Lachlan's comments about Crawley, he didn't push boundaries. Kodak did with Xtol, a complete rethink from their MQ D76 to a PC Dimezone Acorbic developer.

Ian
 

john_s

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That's interesting Ian. I have read this before, from you, about Dimezone (-S?) not lasting as well. I acquired some Dimezone-S years ago for the very reason that it was supposed to keep better in solution, and also be easier to dissolve. I'm not about to do a comparison of shelf lives of developers, but I am curious about the differences. Ryuji Suzuki claimed that Dimezone-S was better in all respects if I remember correctly. Kodak chose Dimezone-S for XTol rather than phenidone.
 

Alan Johnson

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Lachlan Young

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Ian Grant said:
One comment I've seen others post online, and I've experienced personally, is when Ilford PQ liquid developers switched from Phenidone to Dimezone they have a shorter shelf life particularly once opened.
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Can't say that the lifespan of PQU concentrate is any different to Multigrade concentrate in my experience - but that's with the 5L package. My own suspicion is that there may have been a sequence of other small changes when it was reformulated from Phenidone to Dimezone S, possibly affecting buffering capacity in some circumstances - and that either use-case scenario testing didn't cover that - or it was felt immaterial within average throughput usage.

Ian Grant said:
Another comment was Crawley's use of 3 developing agents in some of his Paterson developers, which he said was unnecessary.
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That's about the least surprising thing I'd have expected to hear from a senior researcher, given what we now know about the extent of industry knowledge about Phenidones and the ways that their characteristics can be exploited - alongside HQ (or in-situ formed HQMS at least) by that time - I think the problem is that people have kept stumbling around without realising that beyond the commercially released PQ developers, there's a huge array of potential formulations covering almost all needs (unless zero development inhibition effects are required) largely by varying P:Q (or HQMS or Ascorbate) ratios, then choosing to aim for a pH optimised for either higher definition or finer granularity - and the extent of silver solvency desired to release the development inhibiting byproducts from the emulsion(s).

Ian Grant said:
Also, it appears that in PQ developers substituting Phenidone with Dimezone doesn't give quite as fine grain.
Click to expand...

I wouldn't be surprised if there had been slight reformulations en route - and/ or that there has been slight adjustment of P:Q to increase the development inhibition effect. It's highly probable too that the warmer tone from Phenidone (vs Metol) containing paper developers that you've commented on has a relationship to Phenidone's inhibition effects too - and that it seems little explored.
 
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