Vitamin C in divided developer?

Well, that URL didn't come through well.

Here is another try.

http://www.dequest.com/pages/products/product.asp?id=125

PE

Ok, I hate these edit programs that think they know better than what you do. The URL is product/product/asp. Now I hope that comes through. It is the word product twice with the slash between them and another before the asp.

PE

I haven't seen it mentioned yet, so I'll mention Barry Thornton's DiLuxol Vitesse which is a two bath developer containing phenidone, metol and ascorbic acid. I've used it quite a lot and find it similar to Diafine, but with lower graininess.

(there was a url link here which no longer exists) is a high-SBR example of TMX in DiLuxol Vitesse that I took while evaluating the combination.

Best,
Helen

Photo Engineer said:

.

Ryuji, I know what you said.

I remind you that often things don't work out in practice the way they should work in theory. We have disagreed on a number of things which theory says will not work or would work poorly, but which work well in actual practice for one reason or another. I find it better to test something and possibly learn something new, than pass up an opportunity based on theory and miss something.

This is sometimes called 'intuition' and sometimes 'creativity'. Please don't dismiss the possibility that something just might work. Remember, theory says that insects cannot fly. That was 'proven' through math models.

See for example, "Science Friction" by Dr. Michael Shermer for an excellent and sometimes amusing treatment of this type of mindset.

PE

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PE, I take back all (at least most of it) bad I ever said about you. Some professors from a prestigious science and engineering learning institution told some of our experimenters in the 7X10 foot supersonic wind tunnel that their pressure tubes must have been clogged up because the measurements did not agree with linearized aerodynamic flow theory. I doubt Dr. Shermer had that example, but I'm sure he would have appreciated it. The wing section they were testing had a blunt leading edge. Such wings can not be linearized by the ordinary theory at supersonic speed. All it Took to make a reasonable approximation by the linear equations was to realize that there was a detached shock wave on front of the leading edge instead of the neat Mach wave at the "Proper" angle across the wing..

I hope I did not violate anyones patent rights by solving that problem. I'm joking, of course.

Ron, I'm not convinced it would be worth trying, because I think it would cause other problems even if it worked at first. If you believe they should work so perfectly with no ill effect, you should try them and report the results to get your own credit. I have intuition as well as creativity in this area because I have been thinking about this problem very closely for years, and this is what I get out of your comments. If you think you know better, by all means do your own work and prove it yourself. Good luck.

gainer said:

PE, I take back all (at least most of it) bad I ever said about you.

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Patrick, thank you very much. You know, I believe that we are closer together on some things, more than you believe, and as I said before, I do respect and admire your achievements. I am just a bit of a skeptic about some things, and you know what two of those areas are. No need to bring them up at all here. We just know that we disagree on some things.

People can repsectfully and professionally disagree, and still admire each other and even be friends.

And, in any disagreement, often truth lies with neither side, but rather in the middle somewhere.

My best wishes to you always.

PE

Ryuji, in your two-month lifetime experiments with dilute alcohols, were you using one of your DS-series developers? Were they made up with distilled/deionized water or tap water? What was the concentration of the alcohols in the tested solution?

I'm also confused about your "sulfoesterification"... do you mean sulfonation? Reaction with benzenesulfonyl chloride or toluenesulfonyl chloride? How did you do this?

These bis-phosphonate chelants are interesting. I'm having a hard time visualizing the structure of the "hydroxyethylidene" (and couldn't find a structure on the Dequest web site) but the 2000 series are based on some kind of nitrilotrimethylene tris(phosphonic acid). (Like the ligand NTA but with phosphonates.) I don't understand what the photographic problem is here. These are free phosphonic acids but I doubt very highly that they would hydrolyze to produce a free phosphoric acid (how do you break that carbon-phosphorus bond?)

Ryuji, what is the dominant source of iron impurities in developer formulae like those of your DS series?

Test developers are made for testing purposes, but they are more general purpose developers than DS-10, and they don't contain any active means of retarding oxidation, like DS-10 does. For aging test, I use tech/photo grade stock and tap water in one batch and I split it up into multiple vessels. Then one test agent is added to each vessel. The final pH of each test vessel is adjusted with NaOH. These test solutions contain 50g/L of sulfite and they are probably the largest source of transition metals.

I was trying to block alcohol groups, and thought about one thing I could try. What I meant by sulfoesterification is to modify ROH to ROSO2OX by the same ideas as what you mentioned. When the alcohol is heated, mixed with sulfamic (amidosulfuric) acid, this should result (X=ammonium). Same could be done with iminodisulphonic acid, etc. Sulfamic acid decomposes at high temp to sulfuric acid and ammonia so I thought to remove the excess agent this way... but the consequence of residual acid can be too messy to get useful insight out of it, and I abandoned the approach.

About Dequest 2000 series you described, that's not what I remember from when we discussed it before... If the agents are available free of phosphates, it might be worth looking into.

BUT the agents I've found to be useful so far (and I can at least understand how they work, or at least to corroborate with published data to some extent) use, almost exclusively, nitrogen ligands. Along this line, compounds like bipy are useful if safe and cheap alternatives are found. On the other hand, alkanolamines are convenient, practical agents, and they can inhibit oxidation BUT the way it has to be done is counterintuitive, since they are usually used as alcohol, organic base buffer, or something along that line of use. On the other hand, some of the heterocyclic antifoggant analogues that don't function as antifoggants may be useful. Here, the search process is too involved for me.

Presence of phosphate changes the pathway or kinetics of oxidation when peroxide and iron catalyst are present in water. I can read the literature again and come back to you, or send you copies if interested, but what I remember is that, in absence of phosphates, OH. are first involved but this is not detected to the same level when phospate is present. In practice, ascorbate developer containing phosphate can lose ascorbate very fast, and this may happen without discoloration. (Some people might remember my errorneous report years ago when I posted something on this before I run enough testing at various conditions... I regret.)

Ryuji said:

Sulfamic acid decomposes at high temp to sulfuric acid and ammonia so I thought to remove the excess agent this way... but the consequence of residual acid can be too messy to get useful insight out of it, and I abandoned the approach.

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Sulfuric has to get pretty hot before it will evaporate, and by that time, it will probably have digested most organics present. Why not just neutralize the sulfamic?

The Dequest series of sequestrants are quite stable as I have tried to point out. In fact, IIRC, they are accepted as usable in the food industry due to their good stability.

The ones I tested were very low in free phosphates. I did not test them in developers, only in stabilzers.

Check out the myriad of web sites on Dequests.

PE

Kirk Keyes said:

Sulfuric has to get pretty hot before it will evaporate, and by that time, it will probably have digested most organics present. Why not just neutralize the sulfamic?

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Sulfuric acid (practically, sulfate) is pretty much inert to developer chemistry, at least in the concentration range I'm talkinga bout. Sulfamic acid is more reactive and even at room temperature, I am not sure about what would happen in the two months of storage time.

[QUOTES=dancqu]
"You could use sodium bisulfite. An article on pharmaceutical
preservation mentions a ph of 5 and below where sulfite
will preferentially absorb oxygen. That and A. acid
should give a ph in the 3.? range.

Introducing sulfite I believe would ignore Mr. Gainer's
main reason for using A. acid."

For that matter have you or any others tried stock
or concentrate of A. acid alone. It might work for
me as I always keep the two in full very well
sealed glass bottles. I do not keep working
strength solutions.

Other things being equal acid solutions containing
a preferential oxygen scavenger will prolong other in
solution chemistry.

As for complexing agents, the amount of trivia being
passed concerning it is keeping people out of the
dark. Perhaps those in the production for sale
of photo chemistry are paying attention.

I use distilled water and skip the whole matter. Dan

Dan, good point. I would like to add one now. The distillation process, even if carried out using stainless steel equipment can introduce iron (or other metal) contaminants and that is part of the point of this discussion. The metallic parts of the distillation equipment introduces some contaminants. I could include chrome, lead, zinc, bismuth and other heavy metals sometimes used in plumbing and steel making.

In fact, the only 'safe' water is distilled - deionized (DDI) water which is not readily available. We had that at Kodak, but it was delivered in (guess what) - stainless pipes to every lab. We used high quality 316 stainless with stainless joints and welds.

So... Well, nothing is perfect in this world, but we try to make it so. Our water was as low in all contaminants as possible to get practically. Until the day they found a dead mouse in the DDI water tank on the roof (found of course because we had regular inspections to insure the highest quality DDI water). There is still debate on how the mouse got in there. Everything shut down for a day while they purged the lines and tank, and then refilled with DDI water. Later tests showed that there was no 'mouse' effect on any experiments conducted during the time that the mouse was supposedly present.

PE

"Preferential" oxigen scavenger is probably very misleading. Sulfites react with molecular oxygen in a rather different way depending on pH, and that's probably what your source was trying to convey.

I don't agree with Gainer's reason to avoid sulfite, except for cutting pennies of cost. I think it is a bad idea and I don't find advantage in omitting it.

Concentrated ascorbic acid solution is increasingly difficult to keep. It's known that ascorbic acid increases the rate of peroxide formation by impurities.

Your view of distilled water is not consistent with mine. Even if I use very pure water (distilled three times and deionized), the oxidation is quite fast. My reasoning for this is because the significant amount of impurities are brought in by the chemical stock, not by the water. ANSI standard photographic grade chemical stock is not that pure. I'm always surprized at how many people misquotes me on this one alone.

You called it trivia, but to me, everything else is trivia, and the last key technology we need for practical developer formulation is the means of inhibiting oxidation. I have other aspects under control and there is no mystery in them. On the other hand, is there a brave company who is spending research work into new b&w products? That's nice to know.

I think that Ryuji has an excellent point. The impurities carried in by the chemistry are more important than those present in the water. A good argument for photo grade chemicals which are purer than food grad chemicals.

PE

Ryuji said:

"I don't agree with Gainer's reason to avoid sulfite, except for cutting pennies of cost. I think it is a bad idea and I don't find advantage in omitting it.

On the other hand, is there a brave company who is spending research work into new b&w products? That's nice to know.

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My original reason for omitting sulfite was that I did not have any and would have had to wait two weeks to get some my mail. UPS was not as well developed then as I wanted my film to be. I had pure food grade ascorbic acid and some metol and phenidone to play with along with the infamous pHPlus. Later I concluded that with glycol as solvent for ease in mixing, sulfite could be added to the working solution or not as desired, and experiments could be done with some developing agents such as amidol which would not last long enough to use in water based stock solutions.

I like the KISS principle, although I sometimes forget to consult the handbook. If I can do an effective job of film developing with 2 or 3 ingredients, I probably won't add any more. Pyro dissolved in TEA is a pretty good staining developer. The most I might add to it is a dab of antifog.

Will some company consider a new BW developer? I doubt it, especially if it has looong storage life.

Photo Engineer said:

The impurities carried in by the chemistry are more important than those present in the water. A good argument for photo grade chemicals which are purer than food grad chemicals.

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Photo Grade only assures the user that a chemical does not contain impurities (past a certain level) which would effect its use in a photographic process. The overall purity of Photo Grade could be less than that for Food Grade.

Gerald, my point exactly.

AAMOF, this is an argument I have been involved in before. I don't wish to start it again here. People seem to think they can use any old chemical source for mixing photographic processing solutions.

PE

Photo Engineer said:

Gerald, my point exactly.

AAMOF, this is an argument I have been involved in before. I don't wish to start it again here. People seem to think they can use any old chemical source for mixing photographic processing solutions.

PE

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You forgot to add "and get away with it." The problem is that you cannot always know when you should get the purest you can or can do as well with less pure. The impurities from one supplier may not cause a photographic problem and those from another may cause a big problem. I always understood your viewpoint.

Lab research, where you test a developer in hopes of optimizing some aspect of it, must use highest grade chemicals. I'm sure that when that is done, you will say "it would sure be great to be able to use less expensive stuff" no matter if it's already cheap. (I have enough Scotch-Irish in me that I will skimp on anything except whiskey. That's why I drink so little, which is a good thing.)

I think most major companies do precise lab work with the best available materials. I'm also sure they will also do experiments to see what tolerances in manufacturing and chemical quality can be allowed. We don't get rich by saving a few pennies on developer, but the large companies do.

Patrick, I agree to an extent, as you know. The problem is that we cannot predict that "get away with it factor" very reliably when using some chemicals or sources of chemicals. That is why I suggest starting with the highest purity chemistry in order to avoid untraceable problems in the 'system'

No need to rehash this over here. We know what we want individually and our friends out there reading this can do whatever they please based on their individual budgets.

PE

I checked the MSDS of ph-up - 99.9% pure anhydrous Sodium Carbonate - I use tap water. Any chemical I can get from a cheaper source I use. Ascorbic Acid is from Trader Joes. Sodium Ascorbate is from a Nutrition Center. - Sodium Chloride is from my kitchen - so is Sodium Bicarbonate. I have never had inconsistant results or chemical failures. I also use a calibrated precision scale accurate to .001g - I just don't see anything that won't work if it is within a tolerance of measurement or purity. I believe that tolerance to be pretty wide.

You have to understand that I was on the other side seeing customer complaints sometimes and trying to figure out what they did wrong. Like using kitchen salt which contains an anticaking agent and iodide and which then is present in the wrong amount with what amounts to a small amount of 'poison' in it (Up to a 10% error due to the anticaking agent, depending on the salt will cause problems, and iodide present in varying amounts will do harm to papers). Pool carbonate contains 2% impurities, of who knows what... And here we go again.

You do what you wish, but please please please don't call Kodak, Ilford, Fuji or any of the other major manufactureres if you get into trouble. They just tear their hair out. The customer in trouble does not normally call the person who posted the formula or who suggested using table salt, they call the manufacturer and ask "whats wrong with your film or paper".

Tolerance is not as wide as you may suspect, but I admit that it is wide, for just such contingencies. I have done concentration series of critical ingredients in developers to observe these types of effects and study them. The pH and halide content of developers are both very critical items. The balance of halides in developers is often critical, but that is more in color processes than B&W. The presence of iodide in paper developers is not very good but that depends on the paper.

I don't want to continue to revisit this, it is a fruitless argument with sucesses and failures both. It does work, but not all the time. Who here reports their failures. "Today I ruined my film because I was penny wise and pound foolish. I have to go and reshoot tomorrow at my own expense. What an idiot I was. I used Aquachem pH adjust carbonate to mix up my D72".

Or, I used 3 tablespoons of NaBr from X company and it behaved differently than 3 tablespoons of NaBr from B company. Gee, one was powder and one was cubic crystals. (well, I have that situation in 2 bottles in my lab right now and by volumetric measure there is a 20% difference in weight between equivalent volumes of these two samples). I could go on and on an on. I won't. You do what you want. Lets stop it right here and say we differ and part amicably on this subject.

I'm afraid that the professional in me though does force me to make such comments. Sorry.

PE

gainer said:

(I have enough Scotch-Irish in me that I will skimp on anything except whiskey. That's why I drink so little, which is a good thing.)

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I suspect you don't have enough Scotch because you spelled "whiskey." I have too much Sangiovese and Torrontes in me tonight but I can spot that out. (and I'm very bad in spelling and grammar as everyone knows. I don't blame Italian or Argentinian beverages for that, though.)

fhovie said:

I checked the MSDS of ph-up - 99.9% pure anhydrous Sodium Carbonate

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I have to remind you that MSDS is not a certificate of analysis that comes with analytical reagent chemicals. Whatever that shows up on it is for safety purposes only, and should not be taken as an indication of purity.

Ryuji said:

I suspect you don't have enough Scotch because you spelled "whiskey." I have too much Sangiovese and Torrontes in me tonight but I can spot that out. (and I'm very bad in spelling and grammar as everyone knows. I don't blame Italian or Argentinian beverages for that, though.)

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I wondered about that spelling, but didn't bother to look it up. As a matter of fact, I have not had anything stronger than wine from a local vineyard in my house since I moved here in 1986 and my father had not had any strong liquor since he built the house in 1963. There is a thing about Irish, and I shouldn't leave out my mother who was born in Poland, that is illustrated thus. Someone asked an Irish story teller "Was that a true story?" to which he replied "Ah, well, maybe not, but there's truth in it."