Organoleptic properties of Harvey's 777 type developers

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Lachlan Young

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What you are telling sounds interesting, perhaps you could give a published reference? Were you one of the participants? Anyway, you would agree that in a corporate structure, such as Kodak or Ilford, some people do the R&D and others make decisions as to where the company would go, and those are not necessarily always in agreement. It is pointless to see chemical or economical reasoning in this. Speaking of Haist, he reiterated the message of how important it was to go for the least toxic ingredients, as he mentioned that large numbers of untrained (in chemistry) people were entering photographic processing. So, suppose someone's developer contains p-aminophenol, p-phenylendiamine and hydroquinone, each necessary to its unique properties. This kind of composition is totally in disagreement with the low toxicity trend. However, you can also envisage some propaganda moves to discredit certain chemicals in favor of others. If you ever had a look into what women all over the world stick onto their scalp when they dye their hair, you would know what I mean. BTW, "low toxicity" does not mean you can be careless around developers containing phenidone and derivatives.

No, just have an interest in emulsion making from what I've read on this forum and elsewhere - there's a lot of good stuff in the emulsion making subforum etc about this, though it can take time to find - mostly in discussions about certain developer formulae containing iodide. And I think a combination of desire for lower toxicity in chemicals likely to be used by home users & a shift in R&D towards colour chemistry is probably what largely ended PPD derivative research in BW developers at Kodak.
 

Lachlan Young

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Is there any connection between Robert Lyon and the name Harvey? The patent covers a synthesis methods for combining three developers into one crystal, so it's well possible that less convenient versions of this developer were around before 1944.

As far as I can tell, Defender marketed 777 for Harvey at some point - Defender was swallowed by DuPont in 1945 after a 'close working relationship' - Defender's coating plant was in Rochester - and Lyon seems to be someone at DuPont who appears on some other patents in fairly unrelated areas in the approximate time period. All tends to suggest that DuPont wanted to get this product/ procedure patented for some reason or other.
 
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Alan Johnson

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This is true, but Robert Lyon was not exactly original in this direction. On Haist vol.1, p.196 we read that first experiments of co-crystallization of two phenolic developing agents in a complex date to Lumiere and Seyewitz, who prepared PPD complexes with hydroquinone, catechol and pyrogallol in 1899. So, Germain fine grain is indeed close (but no cigar), in that it uses the same idea. Harvey was certainly aware of these things. If we recall the "murky" character of 777, it points to the main agent being p-aminophenol, augmented with a ternary PPD complex in the style of Lumiere and Seyewetz.
Any idea what might possibly be the other ingredients in the ternary PPD complex?
 

Rudeofus

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Any idea what might possibly be the other ingredients in the ternary PPD complex?
The Lyon patent gives a range of examples. Typical combinations contain o-Phenylenediamine, Pyrogallol/Catechol/Hydroquinone (also halide substituted and/or methylated), and as a third component p-Aminophenol.
 

Alan Johnson

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https://patentimages.storage.googleapis.com/e4/47/b2/59a88c67799bb1/US2397676.pdf
What the patent does NOT claim is ternary addition compounds (with also sulfite and alkali):
10.... pyrocatechol+p-aminophenol+p-phenylenediamine
11.....hydroquinone +p-aminophenol+p-phenylenediamine
12.....chlorhydroquinone +p-aminophenol+p-phenylenediamine
The reason for NO claim might be that they were already known to be in use.
 
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https://patentimages.storage.googleapis.com/e4/47/b2/59a88c67799bb1/US2397676.pdf
What the patent does NOT claim is ternary addition compounds (with also sulfite and alkali):
10.... pyrocatechol+p-aminophenol+p-phenylenediamine
11.....hydroquinone +p-aminophenol+p-phenylenediamine
12.....chlorhydroquinone +p-aminophenol+p-phenylenediamine
The reason for NO claim might be that they were already known to be in use.
My question about pH of the 777 is a way to select between the alternatives that were actually used in the very first version. Any of these three combos would produce a useful developer, with the leading agent being p-aminophenol and some of the organoleptic properties as described in various places, with #10 having the strongest "medicinal" smell. They also fit Harvey's statement of his developer being as "different" from both Sease 3 and D-76 as they are from each other.
 
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Pixophrenic

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Is there any connection between Robert Lyon and the name Harvey? The patent covers a synthesis methods for combining three developers into one crystal, so it's well possible that less convenient versions of this developer were around before 1944.

You can fit Edwal 12 and 20 into this concept, although they can also be viewed as Sease developer(s), augmented with metol or p-aminophenol, respectively.
 
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Pixophrenic

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Unfortunately, his history is also mixed up - and it's slight errors like attributing the faults of Microdol to DK-20 that lead to popular opinions that mislead about the strengths & faults of various formulae.

From the available sources written by & patents awarded to Henn et al: DK-20 could produce 'scum' under certain circumstances in replenished systems, so D-25 was evolved, but it was felt too slow acting for professional/ machine use & Microdol was the result. Dichroic staining from Microdol led to Microdol-X which has a powerful anti-stain agent in it - which we now know to be chlororesorcinol - which was so effective that it & similar chemicals are now included in emulsions.

This is a distracting question, but I just looked into Henn's patent on chloro-resorcinol and it is not about grain, it is about suppressing silver stain in fine-grain developers containing over 75 g/L sulfite. Perhaps I missed some part of this discussion, but how does it all relate to 777? And while we are at it, could anyone point me to a film which <currently> produces this kind of "stain" in DK20? I just tried it on a clip of FP4 with three different concentrations of thiocyanate, and there is no silver stain. It is true that the grain is somewhat finer, but the look of the negatives is otherwise unimpressive. So, does this mean FP4 has chlororesorcinol incorporated in the emulsion and it is pointless to use DK20 with it?
 

Lachlan Young

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This is a distracting question, but I just looked into Henn's patent on chloro-resorcinol and it is not about grain, it is about suppressing silver stain in fine-grain developers containing over 75 g/L sulfite. Perhaps I missed some part of this discussion, but how does it all relate to 777? And while we are at it, could anyone point me to a film which <currently> produces this kind of "stain" in DK20? I just tried it on a clip of FP4 with three different concentrations of thiocyanate, and there is no silver stain. It is true that the grain is somewhat finer, but the look of the negatives is otherwise unimpressive. So, does this mean FP4 has chlororesorcinol incorporated in the emulsion and it is pointless to use DK20 with it?

It's tangential to the 777 ingredients list, but the popular history states that DK-20 produced staining, when the actual commentary from Henn etc when introducing D-25 & Microdol (not Microdol-X) was to do with scumming problems in deep tank systems & replenishment. You should probably have no problems with DK-20 & modern films - indeed thiocyanate is a good silver solvent which has significant potential to offer finer & sharper grain (there is much discussion elsewhere on Photrio about the use of silver solvents & their relationships with higher iodide content emulsions, often taking off from threads discussing reversal process first developers). Microdol-X had the added anti-stain agent discussed in that thread - PE states later that similar chemicals are incorporated in emulsions today.
 
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