Hydroquinone ratio of Kodak HC110 developer

Hello. Does anyone know the ratio of Hydroquinone in HC-110

developer "syrup". Knowing the grams/cc of syrup would help me in

some work. Thanks, Bill

According to Anchell & Troop in their "Film Developing Cookbook", a "rough idea" would be 6g/liter.

It's a very "rough idea", though; the formula for HC110 has changed many times during manufacturing.

In some experiments I did and reported in Photo Techniques I found that adding hydroquinone to HC110 made little or no difference in activity. I concluded that the ratio of hydroquinone to whichever derivative of phenidone (I would guess dimezone) Kodak used is about optimum. Adding hydroquinone to an optimum mixture increases capacity but has little effect on activity. That being said, I cannot really answer your question because I don't know the optimum ratio. All I can say is that there is no peak in activity as hydroquinone is added to a superadditive mixture with constant phenidone, but an asymptotic approach to a maximum.

 

I do know for a fact that adding a mixture of ascorbic acid and triethanolamine to the HC110 syrup will increase the activity of the various dilutions.

Patrick, are you controlling for the pH as well?

 

Adding chemicals to some solution can change various parameters and you are never sure of what is in control of what you are observing unless you control all critical parameters.

 

Adding hydroquinone can change developer concentration as well as pH. Adding triethanolamine and ascorbic acid can also change both. You can't relate what you see in relation to superadditivity unless this and a few other factors are considered. Levenson did a lot of important work in this area in 1940s. A lot more details were worked out during 1970s by other people. Some of them actually used ascorbic acid as the developing agent for good reasons.

Your are right that pH can change things a lot. The experiment that I did before I added the ascorbic acid-TEA mixture to HC110 was with sodium ascorbate in a PQ developer that I knew the composition of. When the hydroquinone is at a certain ratio to the phenidone, adding more does little. Adding sodium ascorbate, which is fairly close to a neutral salt from what I have read, 7.6 or so in fairly high concentration, had a large effect at a working concentration of about 2 g/l. What I think I found out, without trying to explain it theoretically, is that the constant concentration of phenidone still activated the ascorbate even after it had quit activating extra hydroquinone. Whether that is worth anything but an "Ah, so" or not I don't know.

The HC110 was a good candidate for perversion, as I like to call it, because the stock is in glycol and uses something akin to TEA as alkali. I had added ascorbate to it before, but to the working solution. This was my first attempt at perverting the concentrate. It works well, and I use it also as a paper developer with a little more alkali.

Patrick - I think you didn't get my message. I meant that if you don't monitor and control for the pH, whatever you get out of your experiments are uninterpretable.

 

pH of an agent alone in water and the pH effect of that agent in solution together with other compounds are different stories and you can't take one and argue the other without hard evidence from measurements, except for a very simple acid-base reactions for which calculation works reasonably well.

 

"What I think I found out, without trying to explain it theoretically, is that the constant concentration of phenidone still activated the ascorbate even after it had quit activating extra hydroquinone."

 

This is exactly the sort of thing that puts you into troubles, I think. I wouldn't draw any conclusion without more specific experiments with major variables under close control.

What knid of trouble? What I did and what I found is in print and anyone who wants to can play with it all they want. Measuring pH is as much a headache as trying to guess that it didn't change. If I had done the measurement, you would be saying I didn't do it right. Do you have some other reason for doubting that ascorbate and hydroquinone can share the same phenidone? The hydroquinone must have some sulfite in order to synergize with the phenidone while the ascorbate needs none. Will you question that also, just because I say it? The scientific approach when you doubt someone's conclusion is to repeat the experiment doing the measurements that I left out. If it's not that important,why complain? If you are bent on complaining, then do the experiment to show you have a valid complaint. I maintain that the concentrations the I used did not have sufficient effect on pH to make the difference I got. Meanwhile, I will try to find the issue of Photo Techniques that had my article so I can tell you where to find it.

Don't worry my subscription of pt was cancelled some years ago.

 

here you need to see how superadditivity works. you got some pieces but not the whole picture.

 

superadditivity works because the weaker agent can adsorb to silver halide crystals and transfer electron from the stronger agent to the grain. so phenidone is an electron transferring agent. the main developer, hq or asc, passes electrons to phenidone. phenidone, when it loses eloectron by passing ot tpothe agx, becomes some sort of phenidone radical. phenidone radical either gets broken down or get electron and get revived. hydroquinone can give it to electron and it becomes similarly unstable state. now it breaks down. the brokwn down hydroquinone junk impedes the operation of young fresh hydroquinone and so the junk must be swept away somehow. sulfite can do it, ascorbate can do it. in different ways. oh so what, here's a new possibility that is precluded in your theory.

 

in reality, what mechanism is in operation is very difficult to figure out.

G.I.P LEvenson did great work in this area when instruments were so crappy and limiting. people also tried figure out why pq is so much more vigorous than mq. it turned out that phenidone radical was a lot more stable and als wasn't lost in developer solution unlike metol, which is easily lost similar to how hydroquinone junk gets swept away.

 

i'm not inventing or discovering anything. i'm just telling you upshot of what people already figured out and you are precluding so many other possibilities.

do you see what the trouble is?

Does this mean you have matched theory with the facts and found that I did not really see what I saw? There are so many theories about what might have happened that someone with the proper lab equipment should investigate. The trouble is that what I saw looks like a catalytic effect as long as the phenidone itself is not oxidized permanently. It may not be what actually happens, but neither is what happened in our analog computer at NASA when we used it to drive a simulator of an airplane or space vehicle, or a human operator for that matter. Those were the days before digital computers had high enough data rate to simulate dynamic systems in real time. I digress. I'm getting good at that. It's got to be old timer's disease.

Before getting dogmatic, I recommend you to go get original reports and read what they were testing at what conditions and see what redults they got. Think about the results yourself and see if you agree with their discussion. If you question their data, you are welcome to repeat their experiments. If you agree with data but question discussion, talk to the author. Levenson has written a few good review papers on superadditivity as well.

 

There is no need for bad rhetoric. You are saying there are many theories about development and you are implying none of them is useful except yours. I disagree. Major theories, like charge-barrier theory of James, surfactant classification of Umberger, superadditivity of Levenson (and also others mentioned here), electrode process of Pontinus and others, etc. are concerned about different ways to look at development and they are in large part complementary. It is very useful to have them all. If you want to make a career out of making developers, you should regard them as prerequisites as well.

 

One should also keep in mind that we already have enough developers that produce the same results. Before adding another to the formulary, think about what new advantage is offered with that formula. All those middle of the road approach is fully exploited. I personally believe that in this digital age we don't need another so-so developer. We need a couple of BESTs and stick with them. There is an area of darkroom chemistry which is practically left undeveloped for decades, toning. There is another area of photographic chemistry which precluded amateur access for decades, namely emulsions. Developer is nothing like these and we already have enough of them. What we need is more of a weeding out process rather than adding more weeds.

Patrick wrote - "Measuring pH is as much a headache as trying to guess that it didn't change."

 

Well, theproblem it that it may not be a very accurate guess! And look at the headache it has caused you by not measuring it.

 

Really, how hard is really measuring the pH? PAtrick, you could even make one with a little silver wire, some easy to make solutions, and a millivolt pH meter. New ones are not that expensive.

 

It's making the measurement is really pretty easy - calibrate meter - stick probe in solution - stir for a few seconds - read number off display. Pretty easy.

 

And it also covers your butt when people question on what you did...

I don't have to defend my developers any more than whoever dogmatically decided that D-76 must have 100.00 grams of sodium sulfite. I don't care what the pH is if the developer works. I cared what ratio of hydroquinone to phenidone or ascorbate to phenidone was best, if there is a best, and did what most people do when they want to "tweak" a developer. I added a known amount. It was a matter of interest to me and I thought it would be to others, so I submitted it for publication. I know all the difficulties involved, and I seriously doubt that change in pH had a serious effect on what I did, and it is up to someone else who thinks I was wrong to prove it by their own tests. Let me state what I think I learned. When the maximum effect of the synergism between hydroquinone and phenidone is found by adding more hydroquinone to a mixture while holding concentrations of all other ingredients constant, the activity of the developer can be increased yet more by adding sodium ascorbate. That seems to indicate that the same phenidone can activate both hydroquinone and asco0rbate. If you don't believe it, do your own tests of what you believe.

What a surprise!

 

Patrick, if you publish something about developers, you need to understand the importance of the pH and other variables, and means of measuring and controlling them.

 

"When the maximum effect of the synergism between hydroquinone and phenidone is found by adding more hydroquinone to a mixture while holding concentrations of all other ingredients constant, the activity of the developer can be increased yet more by adding sodium ascorbate. That seems to indicate that the same phenidone can activate both hydroquinone and asco0rbate. If you don't believe it, do your own tests of what you believe."

 

You are arbitrarily assuming that added ascorbate has no influence to the development other than through the superadditive effect with phenidone. I don't have much objection to what you observed but I have huge objections to your interpretation of the observation, especially in absence of control of pH.

The formula in the patent (US 3552969) lists 90 grams of hydroquinone per liter of concentrate.

 

Jerry

Forgot to add that it also lists 5 grams of either Phenidone or one of the substituted Phenidones. I can't seem to get the Patent site to display images so I am not sure as to the exact form.

 

Jerry

"You are arbitrarily assuming that added ascorbate has no influence to the development other than through the superadditive effect with phenidone. I don't have much objection to what you observed but I have huge objections to your interpretation of the observation, especially in absence of control of pH."

 

Not exactly arbitrary. Ascorbate without phenidone in the solution I used is practically inert as a developer. So is hydroquinone. So is phenidone alone in the concentration I used. Time of course is a factor. If you're willing to wait long enough, a lot of thigs will produce an image. Just light without any developer will do.

 

The conventional scientific criticism of one's work is to show conflicting experimental results. The ingredients I used are plainly listed in the report for anyone to contest experimentally. I don't have a pH meter. There are more important uses for my money. I do know that sodium ascorbate alone takes a pretty high pH to develop anything before the next millenium, and then it takes a large dose of antifoggant to make a usable image.

 

Somehow I didn't put you in the same category as the MIT faculty who said some wind tunnel data from the supersonic wind tunnel at NACA must be wrong because they do not agree with linearized potential flow theory. They didn't bother to look at the wing section that was being tested. If they had, they would have seen it was outside the boundaries of linearization established by the author of the theory. I still hope you are not one like that.

That is very arbitrary. Gainer chooses to consider the possibilities he likes, and he disregard other possibilities for which he lacks instruments or knowledge. And when the deficiency of technical background becomes obvious, Gainer appeals to those favorite NACA/NASA stories. What does that tunnel have to do with developer? Does that stuff help understand Gainer's arguments? Absolutely not. He may be begging people to accept what he says because of those unrelated stories, but any reasonable reader can tell that distinction. Appealing to NASA to say Gainer is right about photogrephic chemistry is a well known class of logical fallacy, commonly referred to as "fallacy of irrelevant appeal to authority" or Argumentum ad verecundiam. Anyone who took a decent undergrad philosophy class must have heard of it.

 

Another of the problems is that Gainer fails to distinguish between experimental results and their interpretations. I need not repeat his experiment. I am saying that his interpretation of his own experimental data lacks sufficient basis and is arbitrary. There are other possible ways for the interactions between sodium ascorbate and the other elements of the host developer, such as influence on pH. He did not know whether the developer's pH dropped when extra hydroquinone was added. He did not know whether the developer's pH increased when sodium ascorbate was added. Without close monitoring and control of such a critical variable as pH, and without careful consideration and elimination of other possible interactions, he is arbitrarily attributing any change he observed to phenidone-ascorbate superadditivity.

 

Through discussion in this and other threads, I now know it very well that Gainer keeps the main issues all in vague form and introduce irrelevant stories, far fetched arguments and any other means to defend his arguments. He does not accept limitations in his approach and try to improve from there. His arguments are often logically fallacious even before revealing weakness in experimental strategy and interpretation. I don't expect that anyone will learn anything useful by continuing this type of discussion, and I hope to end this thread. I would rather talk about photography and science than fallacy and bad rhetoric.

 

Some readers following related threads may find that he often receives this type of criticisms from several experts. Some are gentle, some more blunt. Gainer is trying to maintain his expert status in the wrong field, and this behavior itself is enough to drive some people to elucidate problems with his approaches and arguments.

Patrick;

 

pH is so important in photography that I went out and bought an excellent pocket sized pH meter for about $150. It was worth it.

 

As for references, the work by Rex Pontius is very nice, but I recommend to you the work of Roland Willis et. al. Roland took over where Rex left off when Rex retired from EK. I knew both of them while at EK, and still see Roland from time to time. Next time I see him, I'll recommend this site to him. If he gets on here, I'm sure he will be more than happy to correct any errors in your posts.

 

BTW, your use of terminology is incorrect in several places using for example 'catalytic' when you should use 'synergistic'. It is quite clear that you are not a chemist. When you mix developing agents and see an increase in development rate, you are observing superadditivity or a synergystic effect. Also, catalysis in photography, when it takes place, can be of two types. Several of my patents cover one of these types. I'll leave it to you to look them up if interested.

 

Patrick, please have your work and comments vetted by a chemist before you post them. Give that person credit in your post. Read the prior art before you do something. (And no, I don't want to vet your work, Kirk or Ryuji would serve you better, or perhaps someone in your circle of friends who is a chemist.)

 

Ron Mowrey

I looked up the definition of catalyst in the CRC Handbook before I wrote anything about it. I am not a chemist. I am not a specialist in anything because I learned by associating with some of them that a specialist is one who learns more and more about less and less until he knows all there is to know about nothing.

 

My story about the wind tunnel data had nothing to do with photography. It had to do with erudite people who knew theory but did not know how to apply it. We have those in every field. When anyone in any field tells me that any theory tells him that what I saw could not have happened because it doesn't agree with theory, I get a little touchy. I had hoped you fellows would have been smart enough to see the analogy. You have told me at various times that theory says my experimental data is in error. I need more than theory to prove that, and so should you. I seek data from other sources that either confirm or refute what I say about the original data. It is a grave error in scientific method to do otherwise. No amount of data can prove a theory right. The best we can do is to not reject the theory when data agrees.

 

It is OK for you to tell us what your mentor taught you, but not for me to do the same. Well, what he taught me was to read reports, and to learn to filter out the hogwash.

Patrick;

 

About 50% of the data from Titan, sent by the ESA probe was lost because a NASA tech forgot to flip a switch so Cassini relayed only 1/2 of the data from Huygens.

 

Were you his mentor when you were at NASA? Just kidding.

 

But I used that to show that even well trained NASA engineers and technicians err even working within their area of expertise, just as you are (or anyone is) more prone to err when outside your field.

 

Ron Mowrey

No, the kid I started off was a candidate for Doctorate in mathematics. He didn't know anything about the physical world. His brother had to change the ignition points in his car.

 

My line of research changed from analysis of flight test data to simulation and human factors, but not specifically for space. Most of the human factors research was into making piloting of aircraft easier. I did design a star projector such as is used in planetariums so that we could use a surplus inflatable radome as a planetarium for some lunar landing and other simulations.

 

People make mistakes, sometimes huge ones. The decision to lift off the Challenger (was it? I've had encephalitis in the meantime) in cold weather was a bad one. That, I think, was management, not engineering.

By the way, Ron, you really should read up on your subject. T. H. James in his dissertation on The Mecanism of Development, in Theory of the Photographic Process, states that silver is a catalyst for hydroquinone and other agents in development, both physical and direct. The action of phenidone and other developers of short induction period it to provide the silver that acts as catalyst for the more active but more delayed agents, so it appears that the phenidone is a catalyst when in fact it is (probably) manufacturing the catalyst. This in turn greatly shortens the induction period of hydroquinone or ascorbic acid at low pH, and the Q or C (for short) regenerates the P.

 

The following is a quote from what I said when I wrote about it in Photo Techniques.

Quote:

" The CRC Handbook of Chemistry and Physics tells us:

"The catalytic agent affects the velocity of a chemical reaction by its mere presence. It is not altered or diminished by the reaction and may be recovered in its entirety at the end of the reaction. "

By that definition, I guess the superadditive development process could be treated as a catalytic process. This idea is not original with me. Some pretty sane people have at least thought about it. In a PQ developer, the phenidone is thought to speed up development by reducing the induction period of hydroquinone at low pH. The hydroquinone is really the primary developer. It is oxidized in the acts of reducing halides and keeping the phenidone from being oxidized. The presence of sulfite ions is required for this process. Ascorbic acid salts perform a similar function in PA developers, but sulfite is not required.

If it helps to lead to some interesting experiments, I can pretend that development by super additive pairs is a catalytic process. Call it "quasi-catalytic" perhaps. "

End quote.

Patrick;

 

In catalysis, one of the agents involved must remain unchanged while changing the other ingredients, and this is surely not the case in the overall reaction scheme.

 

So therefore, in hydrogenation, the palladium catalyst may be used over and over and over again, while the hydrogen and other reagent react one time.

 

The reverse is true in development where HQ and Metol are both used up, each will react with a latent image alone, but both react much much faster and efficiently when mixed. This latter is the definition of superadditivity or a synergistic effect.

 

It is your misunderstanding of chemistry that is leading you astray in your fine interpretation and use of the definitions. Patrick, I have a patent on heterogeneous catalysis at the silver surface with developing agents. Believe me, I'm familiar with the work in this area. Getting a patent is like a thesis defense only harder. You have to conclusively prove that your work is what you say it is and is different than the prior art. I did a lot of reading and research in this area.

 

Read the work of Willis et al on the catalysis with peroxide at silver surfaces, and the reversal of this effect with appropriate agents to get oxidation rather than catalysis. Lots of interesting work there which led to persulfate bleaches.

 

Ron Mowrey

Nevertheless, in the reference I cited and used, it is referred to as a catalytic process. You questioned my use of the term and I gave you the source. I did not make it up.

 

How would the person using a PQ developer, and seeing that the phenidone appeared not to have been used, know that it is not a true catalytic process? If you read the part of my article that I quoted, you see that I did not assert dogmatically that the process is catalytic, but it certainly appears to be.

 

I am still trying to understand what all the furor is about. I very seldom try to define underlying causes for the obervations I make. Those who claim to know the underlying causes have not derived working hypotheses from them, but sit back and say that any empirical relationship or process that I propose must be the result of ignorance. I am ignorant of some things, as we all are. In order to get an answer to some things I want to know, I do something. It may seem stupid to others, but that doesn't bother me. What bothers me is the attitude that these others think they know me the way my friends and relatives know me, and former coworkers knew me. It is obvious to me and to all who know me that you do not.

 

In a former life I solved problems, but not by myself. I was part of a synergistic (you see, I do know the word) interdisciplinary group who fought problems, not each other. If one of us had what seemed to be a silly idea, we laughed and argued and sometimes found it was not so silly, but we never accused one another of nefarious purposes nor of treading on one another's "territory". If that is not how this forum wants to work, then I shall no longer take part in it.

 

Yes, I know about patents. I have applied for them.