Hydroquinone with Metol and Phenidone.

Film Photography & Darkroom discussion

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Ornello
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Re: Hydroquinone with Metol and Phenidone.

Postby Ornello » Thu Apr 29, 2010 3:22 pm

Lowell Huff wrote:I didn't say they were bad formulas. I meant that they would not produce a,scientically measured, difference from other PQ formulas of the "modern" age of chemical formulas. You know, comparing apples to apples.

These are 'modern' formulas...developed in the last few years. What are you talking about?


Keith Tapscott.
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Re: Hydroquinone with Metol and Phenidone.

Postby Keith Tapscott. » Thu Apr 29, 2010 3:39 pm

Lowell Huff wrote:Almost all powder formulas are pre 1920 in origin. As powders they are are not as sophisticated as modern liquid formulas. In pre 1920, Scientists did not have the advantage of all the research into photography that was done in the following sixty years. The pre 1920 formulas were designed for those same emulsions. How many of those emulsions remain today? While those formulas will develop today's emulsions, their lack of sophistication will not "OPTIMIZE" the capability of todays' films and papers. The discussion on their economy of shipping and storage issues does not belong in a discussion of image quality; but i can address it if you wish, in a later "Fataw".
Microphen, uses Phenidone A instead of Metol as the "superadditive", which, in my estimation, makes it an improvement over the older powder formulas. It does not contain any anti fogs or anti cals.
XTOL's claim to fame is that it does not contain HQ as the developing agent. So what? It is a low to medium contrast film developer with all the inherent, well documented problems of mixing two different bags of powder into a liquid. Without HQ it is less likely to oxidize during periods of non use. It can be replenished and can be used as manual or in a machine processor. It is clearly superior to the other developers in this discussion.
If you would like me to compare these chemicals to Clayton's, I can do that. If you did not know, Ilford chemicals are manufactured by Tetenal and Kodak chemicals are manufactured by Champion Chemical.
CLAYTON CHEMICALS are made by CLAYTON CHEMICAL.
Lowell, thanks for the explanation, although I believe that there are sequestering agents in those powders and potassium bromide in Microphen to help prevent fog.

I was aware of the manufacturers of Ilford and Kodak chemistry, although I have never understood why Kodak sold their chemical plants in Europe to Champion and then contracted them to make their formulae. :?:

Optimising formulae for modern materials is interesting, but there are so many claims by different manufacturers that it is no wonder that people keep asking which developers to choose.

Keith Tapscott.
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Re: Hydroquinone with Metol and Phenidone.

Postby Keith Tapscott. » Thu Apr 29, 2010 3:45 pm

Lowell, another question, how does the function of the various Phenidones differ from each other?

Ornello
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Re: Hydroquinone with Metol and Phenidone.

Postby Ornello » Thu Apr 29, 2010 3:57 pm

Lowell Huff wrote:Almost all powder formulas are pre 1920 in origin. As powders they are are not as sophisticated as modern liquid formulas. In pre 1920, Scientists did not have the advantage of all the research into photography that was done in the following sixty years. The pre 1920 formulas were designed for those same emulsions. How many of those emulsions remain today? While those formulas will develop today's emulsions, their lack of sophistication will not "OPTIMIZE" the capability of todays' films and papers. The discussion on their economy of shipping and storage issues does not belong in a discussion of image quality; but i can address it if you wish, in a later "Fataw".
Microphen, uses Phenidone A instead of Metol as the "superadditive", which, in my estimation, makes it an improvement over the older powder formulas. It does not contain any anti fogs or anti cals.
XTOL's claim to fame is that it does not contain HQ as the developing agent. So what? It is a low to medium contrast film developer with all the inherent, well documented problems of mixing two different bags of powder into a liquid. Without HQ it is less likely to oxidize during periods of non use. It can be replenished and can be used as manual or in a machine processor. It is clearly superior to the other developers in this discussion.
If you would like me to compare these chemicals to Clayton's, I can do that. If you did not know, Ilford chemicals are manufactured by Tetnal and Kodak chemicals are manufactured by Champion Chemical.
CLAYTON CHEMICALS are made by CLAYTON CHEMICAL.
That's not quite accurate. Many of the powder developers are much newer than that. D-76 dates from 1927, and I think DK-50 and DK-60a date from the mid-30s (when Kodalk was introduced, I believe), but the much newer developers such as Acufine, Ethol UFG, Microphen, and other PQ formulas are not radically different from those developers. A developer is really not that complicated. You need a preservative (usually), developing agent (always), a restrainer (sometimes) and an accelerator (usually). Amidol does not require an accelerator or preservative, because it is so chemically active, and dies quickly no matter what you do.

The main driving force for modification of developers is the need to achieve better results with 35mm film. This is what D-76 achieved, as the first really mild, fine-grain developer that gave full film speed. Most developers before then had been too aggressive for miniature work, and even after D-76 was introduced, many attempts were made to produce even finer grain using solvent-type developing agents such as paraphenylenediamine. These reduced speed significantly. Kodak developed a formula called DK-20 which used small amounts of sodium thiocyanate (similar to fixer) as a solvent, to try to reduce graininess. It was discarded decades ago, as it produces dichroic fog with modern emulsions.

The production of faster and finer-grained films was the answer, and today's films are vastly superior to what was available in 1927.

Because D-76 is so widely used, Kodak and other companies make their film work well with it.

http://en.wikipedia.org/wiki/Photograph ... er#Formula

http://www.archive.org/stream/journalof ... h_djvu.txt

Lowell Huff
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Re: Hydroquinone with Metol and Phenidone.

Postby Lowell Huff » Thu Apr 29, 2010 4:30 pm

Kieth
The easy answer as to why the various forms of phenidone is, ultimately, the standard curve shape and resistance to heat in high temperature processing.
Ornello
Since I wasn't even a thought in those early years and obviously you were (Ha,Ha,Ha) I will accept your dates. The question was to differentiate between three developers. If D76 was the end all and be all of developers why did scientists develop other formulas to improve the image quality and processing peramiters?

Ornello
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Re: Hydroquinone with Metol and Phenidone.

Postby Ornello » Thu Apr 29, 2010 4:52 pm

Lowell Huff wrote:Kieth
The easy answer as to why the various forms of phenidone is, ultimately, the standard curve shape and resistance to heat in high temperature processing.
Ornello
Since I wasn't even a thought in those early years and obviously you were (Ha,Ha,Ha) I will accept your dates. The question was to differentiate between three developers. If D76 was the end all and be all of developers why did scientists develop other formulas to improve the image quality and processing peramiters?
Where did I say D-76 was the ultimate? It's just a standard that does not excel in any one area but give a nice balance of properties. Most other developers provide more of something than D-76, but at the expense of something else (finer grain but less speed, more speed but coarser grain, better sharpness but coarser grain, etc.). D-76 gives 'standard' fine-grain negatives. I don't use it myself, preferring low-solvent developers. I was using FX-39 and Acutol until a couple years ago when the manufacture was temporarily discontinued. I can't get them in the US anymore. I may resort to FX-37 making it up myself, or I may try Ilfosol, which may be similar to Acutol. Most newer powder developers (such as Microphen or Acufine) could be considered to be merely modifications of D-76.

I generally don't like fine-grain borax solvent developers, preferring Acutol (RIP) and FX-39 (which I can't get here any more; I may try British sources). I don't like or need the solvent action because of my technique, which calls for softer negatives through abbreviated development times, and printing with higher contrast to make up the difference. This produces a noticeable difference in the impression of sharpness and detail.

FX-37 is worth looking at though because it's used diluted.

Most 35mm workers would be delighted with D-76 1:1.
Last edited by Ornello on Thu Apr 29, 2010 5:12 pm, edited 4 times in total.

Lowell Huff
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Re: Hydroquinone with Metol and Phenidone.

Postby Lowell Huff » Thu Apr 29, 2010 4:56 pm

Ornello:
Have you tried Clayton F 76plus Developer?

Ornello
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Re: Hydroquinone with Metol and Phenidone.

Postby Ornello » Thu Apr 29, 2010 5:01 pm

Lowell Huff wrote:Ornello:
Have you tried Clayton F 76plus Developer?
No, and I'm not going to. Nor have I used HC-110 or T-Max developer. Nor am I going to use those, either.
Last edited by Ornello on Thu Apr 29, 2010 5:21 pm, edited 1 time in total.

Lowell Huff
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Re: Hydroquinone with Metol and Phenidone.

Postby Lowell Huff » Thu Apr 29, 2010 5:07 pm

"There in lies the rub"
That is precisely why we are having this discussion.

Keith Tapscott.
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Re: Hydroquinone with Metol and Phenidone.

Postby Keith Tapscott. » Fri Apr 30, 2010 2:34 am

Lowell: I see now that some variants of Phenidone are more robust and resistant than others, depending on applications such as high temperature machine processes etc.

Ornello: I will go along with some of the dates that Lowell provided, as there is an older borax MQ formula that pre-dates D-76 and DK-50 called Wellington Borax MQ. Like wise with simple Metol + Sulphite formulae like Hans Windisch Metol-Sulphite compensating formula which pre-dates D-23 & D-25.

Many of the Kodak formulas are based on European research from companies like Agfa.
Wellington & Ward were taken over by Ilford and Wratten & Wainwright (I think?) were taken over by Kodak.

Ian Grant has an outstanding collection of old text books of various photographic formulae and has contributed to the latest Darkroom Cookbook 3rd Edition and he has shown me the book with the Wellington formula.
http://www.lostlabours.co.uk/photograph ... rmulae.htm

Ornello
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Re: Hydroquinone with Metol and Phenidone.

Postby Ornello » Fri Apr 30, 2010 6:39 am

Keith Tapscott. wrote:Lowell: I see now that some variants of Phenidone are more robust and resistant than others, depending on applications such as high temperature machine processes etc.

Ornello: I will go along with some of the dates that Lowell provided, as there is an older borax MQ formula that pre-dates D-76 and DK-50 called Wellington Borax MQ. Like wise with simple Metol + Sulphite formulae like Hans Windisch Metol-Sulphite compensating formula which pre-dates D-23 & D-25.

Many of the Kodak formulas are based on European research from companies like Agfa.
Wellington & Ward were taken over by Ilford and Wratten & Wainwright (I think?) were taken over by Kodak.

Ian Grant has an outstanding collection of old text books of various photographic formulae and has contributed to the latest Darkroom Cookbook 3rd Edition and he has shown me the book with the Wellington formula.
http://www.lostlabours.co.uk/photograph ... rmulae.htm
The point I was making was that powder developers similar to and evolved from D-76 are state of the art developers, and that D-76 itself is far from obsolete.

Keith: I was not denying that there are older formulas than D-76. Of course there were. Many of them used glycin I believe, and did not use borax but rather carbonates or even hydroxides. The point is that MQ Borax was a breakthrough that is still used. For more details on this I suppose we could consult old BJP Annuals from before 1930.

Murray Kelly
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Re: Hydroquinone with Metol and Phenidone.

Postby Murray Kelly » Fri Apr 30, 2010 10:03 am

Lowell Huff wrote:Guys,
you are mis-informed about the relationship of the accelerators, Metol & Phenidone, and HQ. In the development process, Metol forms a salt with HQ and becomes ineffective. P acts as a catalyst with the HQ to develop the exposed silver and then " searches for the next free HQ molecule", to continue the process until there is no more available HQ. This is the explanation of why MQ developers run "right up to the edge of the cliff and drop in the ocean." PQ developers " gradually slide into the ocean." The real differences and advantages of PQ over MQ are P is about 25 times more active than M, P is much less allergenic than M, P is much more resistant to high temperature (therefore we use it in machine process developers), P can be easily replenished, changing dilutition of a PQ developer will change contrast, and each form of P will change the standard curve to increase number of steps over M.
The advantage of a developer combining both is "bolstered syntax".
Don't you agree that your statement (Underlined) confirms the aforementioned action of HQ at low pH? Don't want to get involved with a one sided argument with a professional, but it seems the HQ does indeed prolong the action of the P and M after they would normally poop out? One could conjecture that lotsa HQ would make a little M or P go a loooong way? Be kind, I'm still learning after 60 years as an amateur.

Ornello
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Re: Hydroquinone with Metol and Phenidone.

Postby Ornello » Fri Apr 30, 2010 10:38 am

Murray Kelly wrote:
Lowell Huff wrote:Guys,
you are mis-informed about the relationship of the accelerators, Metol & Phenidone, and HQ. In the development process, Metol forms a salt with HQ and becomes ineffective. P acts as a catalyst with the HQ to develop the exposed silver and then " searches for the next free HQ molecule", to continue the process until there is no more available HQ. This is the explanation of why MQ developers run "right up to the edge of the cliff and drop in the ocean." PQ developers " gradually slide into the ocean." The real differences and advantages of PQ over MQ are P is about 25 times more active than M, P is much less allergenic than M, P is much more resistant to high temperature (therefore we use it in machine process developers), P can be easily replenished, changing dilutition of a PQ developer will change contrast, and each form of P will change the standard curve to increase number of steps over M.
The advantage of a developer combining both is "bolstered syntax".
Don't you agree that your statement (Underlined) confirms the aforementioned action of HQ at low pH? Don't want to get involved with a one sided argument with a professional, but it seems the HQ does indeed prolong the action of the P and M after they would normally poop out? One could conjecture that lotsa HQ would make a little M or P go a loooong way? Be kind, I'm still learning after 60 years as an amateur.
D-76 without HQ dies rather quickly. The HQ regenerates the Metol. It does the same for Phenidone in PQ formulas. No question about this. What is the issue then?

Lowell Huff
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Re: Hydroquinone with Metol and Phenidone.

Postby Lowell Huff » Fri Apr 30, 2010 10:51 am

"The underlined statement" was my way of describing the action of a catylist forthe chemically handicapped. P will work as long as there is available HQ. At some point the concentration of HQ does become problematic, slide into the ocean.
M froms a salt with HQ and is done, drop in the ocean. The pH of the solution really determines the speed of processing not the relationship between the superadditives.
There are two ultimate considerations in this commentary. The ideal or laboratory discussion and the cost to manufacture and market. Since these two ingredients are the major portion of the formula cost, I as a mfg, balance the formula to be the most profitable with image quality.

Murray Kelly
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Re: Hydroquinone with Metol and Phenidone.

Postby Murray Kelly » Fri Apr 30, 2010 11:03 am

Ornello, the issue boils down to the statement the M is NOT regenerated by HQ. This flies in the face of statements to the contrary I have run down in the e-net. As a manufacturer Lowell should know and I want to clear the point up.
For me, P is expensive and HQ is not. Maybe a POTA with added HQ would allow me to use less, cheaper, HQ to boost P in the brew? Its action in MQ developers at low pH is a curiosity I would like to clarify.


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