Super Fix

garrylewis747 · October 5, 2004

>I made mercury fulminate once.

Gee Kirk, I hope "homeland security" ain't reading this thread.}:^)>

rowland_mowrey · October 5, 2004

And, when I was a teen we used to make nitrogen triiodide, and we let it dry out. It was a fun time.

In fact, if you saw "October Skies" Hmm, or was it 'Sky'? Anyhow we used to build our own rockets and launch them in the baseball field behind our A&P food market. We were on the approach to the old Pittsburgh airport, so we had to watch out for low flying planes.

I ended up working at Cape Canaveral for 1.5 years.

Yes, Lex, I know what you said to me. I'm not going to drop any names.

Now, back to the subject at hand. If there was no need or desire for anyone to mix their own formulas, then there would be no need for books containing all those published formulas for scratch mixing, and there would be no need for scratch mix chemicals to be sold.

I started this thread for two reasons. There is a lot of interest out there to learn, and there is a lot of feeling that photographic chemistry has reached its peak, particularly in stop and fix chemistry, or perhaps in B&W chemistry. There is much to learn, a great bit being as yet unpublished or difficult to find, and research still goes on.

This does not mean that the fix above is safe, proven or practical (able to be commerciallized), but it shows what can be done. Fixes like this one exist that are safe, proven, and may be practical. That will have to be demonstrated in the fullness of time. Those formulations are proprietary and are for others to publish. For now, I repeat, R&D does go on.

I feel compelled to add that if you wish to criticize this thread from the aspect "why scratch mix" or "scratch mixing may be unsafe", then you must in all fairness apply the same criticism to those others who publish home brew scratch mix formulas or those who sell chemicals that are used for this purpose. I don't deny the merit(s) inherent in your comments posted above however.

Ron Mowrey

kirk_keyes · October 5, 2004

I had originally intended to post this info to the stop bath thread of yore, but since that one is closed I figured this would be appropriate.

I'm an analytical chemist, and one of my duties is to do cyanide anaysis on water, wastewaters and solids samples. So, in the past, I had wondered myself about how stable thiocyanates compounds were, especially in solution.

So I ran an analysis on a test solution. The sample consisted of a 125 mg/L (ppm) solution of potassium thiocyanate. I then subjected the sample to 4 different conditions. The first one was to place the test solution into a cyanide distillation still with the solution unbuffered (pretty much neutral pH). The second condition was with the pH adjusted to about 4.5 - this condition was following the method for what is called "Weak-acid dissociable cyanide" - it will liberate weakly held cyanide in compounds like sodium or potassium cyanide. The 3rd and 4th conditions were to adjust the pH to much less than 2 using sulfuric acid. This condition is used in the EPA "total cyanide" method and will break down most cyanide compounds including many complexed cyanides such as ferro- or ferricyanides.

All of these solutions were then boiled for over 2 hours except #4, which was kept at room temperature. Air was pulled/bubbled through each sample during the distillation and any cyanide gas that was released from each sample was trapped in a solution of sodium hydroxide. Each distillate was then analyzed for it's cyanide content. No detectable cyanide was released from any of these four solutions. The test was able to detect cyanide to 0.1 mg/L (ppm).

Now this doesn't mean that you can't release cyanide from a thiocyanate solution by heating it strongly until it decomposes, or by treating the solid material with strong acid, either with heat or not. I did not test for those conditions. But it does mean that you probably have very little risk of releasing cyanide from a thiocyanate solution.

And it doesn't mean that thiocyantes are not toxic. They certainly are - they are probably more toxic than any of the other ingredients in the formula Ron gave above, and you should take appropriate measures to minimize your exposure to them if you decide to use a formula like that.

I would suggest that you wear gloves and not place your bare-hands into the solution as is often done with regular fixes. If some of the solution does contact your skin, wash it off. But certainly a formula like that can be used and with minimal risk.

lowell_huff1 · October 8, 2004

As we manufacture rapid fixer, and we offer five different liquid and one powder products, there is nothing in them more hazardous than acetic acid ( strong vinegar). Ammonium thiosulfate is grass fertilizer. Maybe I minimumize the concern but I don't think so.

We sell raw materials to people who want to do their own compounding because they will pay for the chemicals. I do interview those people that ask for quantities or products that I feel are out of the "norm" of safe to use.

Again, thiourea and thiocyanate have no business in fixer.

rowland_mowrey · October 8, 2004

Lowell;

I cannot disagree with you.

OTOH, I must point out that thiocyanate salts and thiourea are used in a variety of photographic formulas that are prepackaged and sold by the major manufacturers for the hobbyist and professional alike.

I am not the one who originated the use of these compounds for such use. I merely take advantage of their use elsewhere and apply it in yet another useful way.

Ron Mowrey

edward_zimmermann · October 10, 2004

"<cite>As we manufacture rapid fixer</cite>..."

G-d save us. I suspect strongly from your comments that you have not recieved much training as a chemist..

"<cite>Again, thiourea and thiocyanate have no business in fixer.</cite>"

Then tell that to Agfa and Kodak! What do you think Kodak uses in their RA (Rapid Access) C-41 Fix?

<TT>

EASTMAN KODAK COMPANY -- 861 9090,FLEXICOLOR RA FIXER AND REPLENISHER,

=======================================================

MSDS Safety Information

=======================================================

MSDS Date: 05/01/2000

MSDS Num: CKTJQ

Product ID: 861 9090,FLEXICOLOR RA FIXER AND REPLENISHER,CONCENTRATE

MFN: 01

Responsible Party

Cage: 19139

Name: EASTMAN KODAK COMPANY

Address: 343 STATE STREET

City: ROCHESTER NY 14650

Info Phone Number: 716-722-5151/(800) 242-2424

Emergency Phone Number: 716 722-5151

Preparer's Name: NOT PROVIDED

Review Ind: Y

Published: Y

=======================================================

Contractor Summary

=======================================================

Cage: 19139

Name: EASTMAN KODAK CO GOVERNMENT MARKETS CONTRACTS

Address: 343 STATE ST

City: ROCHESTER NY 14650-1115

Phone: 716-722-5151/(800) 242-2424

=======================================================

Ingredients

=======================================================

Cas: 7732-18-5

RTECS #: ZC0110000

Name: WATER

% low Wt: 60.

% high Wt: 65.

Other REC Limits: NOT PROVIDED

OSHA PEL: NOT ESTABLISHED

ACGIH TLV: NOT ESTABLISHED

------------------------------

Cas: 1762-95-4

RTECS #: XK7875000

Name: AMMONIUM THIOCYANATE

Percent by Wt: 15.

Other REC Limits: NOT PROVIDED

OSHA PEL: NOT ESTABLISHED

ACGIH TLV: NOT ESTABLISHED

EPA Rpt Qty: 5000 LBS

DOT Rpt Qty: 5000 LBS

------------------------------

Cas: 7783-18-8

RTECS #: XN6465000

Name: AMMONIUM THIOSULFATE

Percent by Wt: 19.

Other REC Limits: NOT PROVIDED

OSHA PEL: NOT ESTABLISHED

ACGIH TLV: NOT ESTABLISHED

------------------------------

Cas: 7757-83-7

RTECS #: WE2150000

Name: SODIUM SULFITE

% low Wt: 1.

% high Wt: 5.

Other REC Limits: NOT PROVIDED

OSHA PEL: NOT ESTABLISHED

ACGIH TLV: NOT ESTABLISHED

------------------------------

Cas: 10196-04-0

Name: AMMONIUM SULFITE

% low Wt: 1.

% high Wt: 5.

Other REC Limits: NOT PROVIDED

OSHA PEL: NOT ESTABLISHED

ACGIH TLV: NOT ESTABLISHED

EPA Rpt Qty: 5000 LBS

DOT Rpt Qty: 5000 LBS

</TT>

I can provide a long list of items probably already in our darkrooms that contain Ammonium Thiocyanate-- among them Agfa's Sistan.

Many developers (especially in diapositive processes) contain Potassium Rhodanite (Kaliumthiocyanat). Sure you don't mix these with nitric or strong acids, strong oxidizers or heat to high temperatures- - BUT nearly the same can be said of many household cleaning products used in untold millions of households daily. Please also note the SULFITE in these fixers! I won't argue that with some effort one could not probably get some cyanide out--- which despite forklore really demands by comparison to many other gases a moderately sized dosis to produce ill-effects--- but then one can toss a toaster into a bathtub (providing one does not have a working Residual Current Device installed on the power source) or do any number of things to get in harm's way..

If you are not just a stocking boy at the company in question I'd say its more a question of "<cite>your company</cite>" not belonging in the bussiness of selling fixers...

All chemicals CAN provide danger and there is NOTHING safe about strong acetic acid. Stop playing it down. Its not harmless. Even the dillute working-stength bath as used in stopbaths can provide dangers--- and splatters into eyes are NOT that far fetched. One must learn to handle chemicals and its irresponsible to sell ANYTHING to ANYONE where one suspects that they have insufficient training to be able to "within reason" handle the materials..

To call any of these chemicals as "100% safe" gives a false sense of security and opens the way to abuse.. And we MUST ALSO make it clear that ALMOST ALL pre-made photochemicals can be dangerous.. As well as most of what is in our environment.. the cars on the road.. nothing is a "toy".. not even a child's bicycle..

rowland_mowrey · October 10, 2004

Edward;

Thank you.

It is much less self serving when definitive posts come from someone else besides myself when it is suggested that I'm making inappropriate suggestions. You and Kirk have both shown that thiocyanate is used and useful and not overly harmful in photographic solutions.

So, for the others that criticized my formula, this should be revelatory to them, that I actually do know a bit about bleaching and fixing, and what is being used out there.

I would also direct my critics attention to those excellent developers which use thiocyanate as a silver halide solvent to achieve solvent effects without the levels of sulfite used in D76.

The super fix will clear Gold 400 film at 22 deg C in about 3 minutes, whereas F5 barely does the job in 10 mins. That is why RA C41 fix uses the synergy of multiple fixing agents, as was disclosed in the appropriate patents and as Edward shows in his post.

How do I know this? I've BTDT! This is regardless of what some people have said in this and another thread.

I would like Lex to note this also, as the RA chemistry is designed for use in minilabs in malls and supermarkets. This is hardly the place where EK would suggest the use of something that is overly toxic, especially considering the location and the training level of some of the operators that are responsible for the chemistry.

Thank you all.

Ron Mowrey

lex_jenkins · October 10, 2004

I'm aware of the contents of the photochemistry used in typical minilabs, Ron. As an OSHA inspector I saw more than one poorly trained minilab operator suffering from pretty severe skin rashes.

The fact that something is common doesn't mean it's safe. And if there was such a thing as common sense there wouldn't even be a need for the concept of "common sense".

Finally, some of these threads purporting to re-educate fellow photographers regarding their misconceptions have taken an ugly turn toward smugness, providing only an excellent example of why some photographers prefer to get their information from definitive books written by recognized authorities. Or participate on the rec.photo newsgroups.

rowland_mowrey · October 10, 2004

Lex;

Some of the 'recognized' authorities?

While I don't equate the use of a chemical with the saftey of a chemical, I do draw a distinction between reasonable safety and deadly. While I don't approve of it, a rash is hardly in the same category as a sudden case of death. I would never ever condone anything leading to the latter, unfortunately even some of the best photographers develop rashes. I hardly think that one of the major manufacturers would condone the use of highly toxic chemistry.

As you know, a 'recognized' authority has just as much as accused me of condoning the irresponsible use of chemicals here. If anyone is smug or irresponsible, it is some of the so called 'recognized' authorities who have no training whatsoever in chemistry but rather 'decide' to write a book or article about their hobby and 'educate' the masses.

I have seen a recommendation here for people to heat propylene glycol to over 100 degrees Centigrade to prepare photographic solutions. But, the danger is that the flash point of propylene glycol is 99 deg C, thus opening the door to a flash fire. OTOH, we have the danger of a severe burn if there is an accidental spill.*

I have seen a recommendation to heat sodium carbonate to drive off moisture to form the anhydrous form from the hydrate, but if the temperature rises to 400 deg C (which can happen if the user is careless or hasty, or inattentive, and especially if they have a gas stove) the sodium carbonate gives of carbon dioxide and forms Sodium Oxide. This chemical can react violently with water and also produces very caustic solutions.*

I have seen no warnings about these practices when they were posted. So, I'm in total disagreement with you when you recommend users turn to published experts. I even urge them extreme caution using pre-packaged chemistry and the same caution when following my advice.

Ron Mowrey

* Note: all chemical information on propylene glycol and decomposition of sodium carbonate was obtained from the Merck index, twelfth edition.

bill_troop1 · October 17, 2004

OK, here is one of the 'recognized authorities' Ron has such problems with, appearing here much against his better judgment. I want to address only one thing, Ron's avid, multiple recommendations of the simple chemical acetic acid.

Ron writes,

>While I don't equate the use of a chemical with the saftey [sic] of a chemical, I do draw a distinction between reasonable safety and deadly. While I don't approve of it, a rash is hardly in the same category as a sudden case of death. I would never ever condone anything leading to the latter, unfortunately even some of the best photographers develop rashes. I hardly think that one of the major manufacturers would condone the use of highly toxic chemistry.

>As you know, a 'recognized' authority has just as much as accused me of condoning the irresponsible use of chemicals here. If anyone is smug or irresponsible, it is some of the so called 'recognized' authorities who have no training whatsoever in chemistry but rather 'decide' to write a book or article about their hobby and 'educate' the masses.

Strong words, Ron, beautifully expressed, but inconsonant with the facts, and with longstanding industry practice and colored with a little too much bile to be take quite seriously.

Grant Haist devotes nearly a page in Modern Photographic Processing (pp. 546-547) to the danger of the glacial acetic acid you so strongly recommend. "Most published photographic formulas list the use of 28% acetic acid rather than the readily available glacial acetic acid ... glacial acetic acid is a strong acid irritating to the skin and eyes, whose poisonous nature is best avoided under most darkroom conditions. For these reasons, most photographic manufacturers recommend the use of 28% acetic acid ...."

We see here the problem with letting a lab boy out into the world. He doesn't have any experience of manufacturing, and no idea what companies have to do to protect their users. With all his decades of experience, he still doesn't understand why all responsible photographic companies, including Kodak, sell 28% rather than glacial acetic acid to photographers. Our lab boy lacks perspective on anything that doesn't happen outside of his lab.

Ron, before you make any more specific recommendations to photographers out there in the wide, wide world, please talk to some of the safety and manufacturing people at Kodak. You'll learn a lot!

Ron also pooh-poohs the occasional rash, on the grounds that a mere rash is hardly sudden death. But that rash may indicate contact with a carcinogen, or some other equally harmful agent, any one of which could spell serious and ultimately fatal health problems years later down the line, long after the 'little rash' has disappeared.

Ron, I guess you have a profound psychological need to waste Internet bandwidth accusing me of being a hobbyist who 'decided' to write a book, etc. etc. etc. If you have such a problem with that, why don't you write your own book instead of posturing on the web as some sort of virtual father figure to all the orphaned photographers of the world? And why don't you learn something about industrial, manufacturing, and darkroom safety? You are irresponsibly advocating the use of chemicals and procedures that leading photographic manufacturers such as Kodak have condemned for decades. This isn't right. Further, your motives are questionable. You seem to be more interested in attacking me, than in putting actually useful information out before the world. What you are doing isn't a sensible use of your time, and it doesn't utilize the considerable gifts that could make you so valuable to the photographic community.

Can I suggest something? If you want to be a useful member of an Internet forum, your motive has to be to learn, rather than to teach. Believe me, after years of being a so-called authority, I am always amazed at what I learn everytime I go onto a forum.

lex_jenkins · October 17, 2004

For some reason I am reminded of a commentary in one of my favorite PC games about a programmer who "still thinks it's all about him."

Many comments, remarks and obvervations on these forums are intended to be directed to the participants at large and not to be interpreted as a personal affront to any individual.

However I suspect that even this statement will be misconstrued.

garrylewis747 · October 17, 2004

MY GAWD! here we go again!

rowland_mowrey · October 17, 2004

Gary;

Yes.

However, I will quote Patrick Gainer here in response rather than use my own arguments. Then I will have a concluding statement.

Post by Patrick Gainer, October 12th:

"I was in a chemistry lab course at WVU. Certain chemicals, one of which was glacial acetic acid, were kept in large bottles with a blow tube and an exit tube. You blow in the one and the liquid comes out the other. It is essential that the other end of the blow tube be above the liquid level. I was half asleep (my usual state in those days) and didn't notice that the lab assistant had just refilled the jug and had the level above the end of the blowtube. When I let up my breath pressure I got a mouthful of glacial acetic acid. Needless to say, I did not swallow. After a long session at the water fountain, I was OK.

It is remarkable that some will not tolerate chemicals in the darkroom that they keep on a kitchen shelf, such as Drano, which is mostly one of the hydroxides, or Clorox, which you would certainly not want to drink or spill on your clothes."

So, Bill, Patrick does not appear to agree with you.

Also, I am having lunch this week with Grant Haist's best friend before he leaves for Fla to winter with Grant. I hope to get a complete story from him about Grant's health when I meet him, but for the record, Grant had a stroke 4 years ago, and I did see him here during his recovery period. I don't know where Bill Troop got his information, but I got mine from a guy who had just come back from Michigan after several weeks with the Haist family there, who most would consider is Grant's best friend, and who lives near him in Fla. I also got my information in person when I chanced to meet Grant in the mall as I said in the previous exchange with Bill Troop.

I'm getting tired of this Bill. I've had over 40 years of lab experience including photofinishing labs and manufacturing labs as well as research. This includes 7 years of college level chemistry.

My photographic materials budget when working for the government was over $50 Million / year. I know what I'm talking about.

Science is about the dispassionate critique of each others work. That is what I started out with only to see it degenerate into personalities. I have read your other posts here and elsewhere. I have had the URLs e-mailed to me by others here interested in the interplay. I suggest others try reading some those posts.

Ron Mowrey

bill_troop1 · October 17, 2004

>I'm getting tired of this Bill. I've had over 40 years of lab experience including photofinishing labs and manufacturing labs as well as research. This includes 7 years of college level chemistry.

And you still don't understand why photographic manufacturers don't like to let glacial acetic acid into photographers' hands?

>So, Bill, Patrick does not appear to agree with you.

Well, it's Haist and Kodak on one side of the scale, and you and Patrick on the other. Which is heavier?

>but for the record, Grant had a stroke 4 years ago, and I did see him here during his recovery period.

Ron, when you first mentioned this stroke rumour, you used the word 'recent'. Now it was four years ago?

>I don't know where Bill Troop got his information

From a telephone conversation with Haist himself on October 1, 2004.

>I also got my information in person when I chanced to meet Grant in the mall as I said in the previous exchange with Bill Troop.

which you then said was 'recent' and but you now say was 'four years ago'.

>I'm getting tired of this Bill.

Grant Milford Haist is 82 years old. He says he is not now ill and never has been ill. Please stop spreading these ugly rumours.

terry_stedman · October 17, 2004

Bill Troop said:

"We see here the problem with letting a lab boy out into the world. He doesn't have any experience of manufacturing, and no idea what companies have to do to protect their users. With all his decades of experience, he still doesn't understand why all responsible photographic companies, including Kodak, sell 28% rather than glacial acetic acid to photographers."

"And you still don't understand why photographic manufacturers don't like to let glacial acetic acid into photographers' hands?"

Bill, check this out: B&H sells glacial acetic acid made by both Kodak - which you specifically said didn't sell that to photographers - and also Photographer's Formulary. Look <a href="http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=26583&is=REG">here</a> and <a href="http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=123682&is=REG"> here</a>.

Not only does Kodak make glacial acetic acid, they let B&H resell it to anyone.

rowland_mowrey · October 17, 2004

Bill;

Eastman Kodak sells glacial acetic acid in 1 gallon containers and in 6 x 1 gallon containers for about $23/gallon. Look it up on calumetphoto.com or bhphotovideo.com. I bought a bottle last summer. I still have most of it. If it is so dangerous, then EK should not sell it to the average photo hobbyist!

Just like your other comments, the 'fact' that EK no longer recommends glacial acetic acid is wrong. They also sell 28% in pint bottles. Per unit weight, 28% acetic acid is not very cost effective. Like all chemicals both varieties are harmful, but Patrick's statement quoted above stands on its own merit.

Glacial acetic acid is also sold by the Photographers Formulary.

It is as 'safe' as any other photographic chemical.

Your other 'nemesis', thiocyanate, is now used in the new EK Flexicolor C41 RA fixer, which is similar to my formula above except for the thiourea. This is another point on which you are totally wrong. Thiocyanate is not a 'killer' that liberates cyanide easily. You have to pyrolize it in acid. The human body liberates toxic gases if it is pyrolized!

The EK Flexicolor C41 RA fix can be used as a very rapid fixer for B&W films. Ammonium Thiocyanate is also sold by the Photographers Formulary.

I urge the readers here (if any are left after this exchange) to verify all of my comments above. The MSDS post by Edward Zimmermann above should satisfy the thiocyanate information, but it is also available on the EK web site, and going to the dealers sites I mentioned should show the availability of the Glacial Acetic Acid which Bill has claimed was discontinued by EK.

Bill, your information about Grant is 100% wrong! I don't have to explain why or how you are wrong. I have it from two sources and saw him with my own eyes as he confirmed that he had been ill!

I don't know why you took my remark above as directed towards you. You are either a 'real expert' and my comments don't apply to you in any way, or my comment above has hit close to some sore spot and has resulted in this exchange. If you are a real expert, then you have no need to reply to my post above, if not then I can fully understand your concern.

I am not proud of this exchange, but I am annoyed. The readers feel the same way as you might note from Gary Lewis' comment above. I sympathize with them. This should be a factual exchange of photographic information.

Ron Mowrey

rowland_mowrey · October 17, 2004

Terry;

Thank you for putting up that post!

I'm glad to see that others recognize the errors throughout Bill's posts. If I am wrong, please don't hesitate to put up corrections of my statements as well.

Please also recognize that similar errors or misstatments can take place by anyone in any sort of forum or publication.

Ron Mowrey

bill_troop1 · October 18, 2004

> going to the dealers sites I mentioned should show the availability of the Glacial Acetic Acid which Bill has claimed was discontinued by EK.

Bill never 'claimed' this! Ron, if this is how you parse my posts, I'm not surprised you have grasped so little of the photographic literature. Guys, I can't believe that you cannot distinguish between products Kodak intends to be sold for home use and products Kodak intends to be sold for commercial lab use where the chemicals will be handled by trained operators. You've got to distinguish between products which are recommended to photographers untrained in chemistry, and products which are recommended to lab technicians.

You are arguing against the entire historical practice of the photographic industry over the course of nearly the entire 20th century. Let me recap what Haist writes:

"Most published formulas list the use of 28% acetic acid."

"[G]lacial acetic acid is a strong acid, irritating to the skin and eyes, whose poisonous nature is best avoided under most darkroom conditions."

"For these reasons most photographic manufacturers recommend the use of 28% acetic acid for making stop baths and also for making fixing baths where the glacial acetic acid may decompose some of the ingredients, such as the sodium sulfite."

[Haist, Modern Photographic Processing, Vol. 1, 1979, 2000, pp. 547-547]

Ron, that latter point is something you might want to consider as well, the next time you publish a fixer formula.

Again, you have to wonder why, in a highly technical book where some of the most important information must be covered in a sentence, Haist devotes nearly a page to this issue. Obviously, he considers it important. Ron, of course, may disagree. But Ron: did you put your objections to Haist? And did he incorporate them? I am searching for a footnote which says "Ron Mowrey disagrees with this." I haven't found it yet.

Again, let me emphasize the point: what you can recommend for laboratory or commercial process is not what you can recommend for the average photographer's darkroom, given that the average photographer has no training whatsoever in the safe handling of chemicals. It is no defense to say, oh, all chemicals are dangerous. Manufacturers have universally recommended 28% acetic acid throughout the 20th century. See also Crabtree and Matthews, Photographic Chemicals and Solutions, pp. 272-273 regarding the handling of glacial acetic acid: "Suitable goggles should always be worn to protect the eyes against acid burns." (How many photographers wear goggles in their darkrooms?)

In the Focal Encyclopedia, 3rd ed., 1993, Haist wrote, "corrosive liquid" and "a photographic grade (28%) is more practical ...."

28% is considered the photographic grade.

Regarding the handling of ammonium thiocyanate, Haist wrote "Wear safety glasses and rubber gloves. Wash thoroughly after handling as the compound may cause skin eruptions. May be harmful if inhaled or swallowed." This contrasts with his safety recommendations for ammonium thiosulfate where he merely writes: "Use the normal safe practices of the darkroom and laboratory."

anders_br_the · October 18, 2004

Dear mr. Troop. I have bought and read your book thorougly and enjoyed it a lot. It certainly taught me much about the photographic properties about many chemicals in a easy to understand fashion.

What I dont understand is why you respond like you do towards all those that discuss or disagree with things written in your and Anchells book. I have read all your posts and what you do is start out with a personal attack. Why not discuss the matter instead of the person posting? Defend and explain your work, do not attack your opponents.

On topic; glacial acetic acid is not a strong acid. It is a weak acid! It has a pKa of 0.000018, and will of course dissociate to a very low degree. A quick calculation tells you that about 2.3% of the acetic acid is dissociated at 2% concentration. Degree of dissociation will decrease at higher concentrations. Sulphuric acid, which is indeed a strong acid, will protolyze fully in the first step. There is a considerable difference between a strong acid and a weak one. I have spilled both of these acids on my hands by accident, and I consider acetic acid to be a relatively harmless chemical. Much less harmful than the stuff you buy at the supermarket to clean up your drains, which is sodium hydroxide. Strong bases are much more harmful towards human tissue than acids. Still, it is sold and used by people with no formal training in handling chemicals.

I would say anyone who cannot safely handle glacial acetic acid safely have no business handling darkroom chemicals at all. There are many developing agents commonly used I would handle with greater care.

And for the sake of decency; stop pushing Dr Haist in front of you as your witness of truth. Fight your own wars, do not pull in an innocent third part.

conrad_hoffman · October 18, 2004

FWIW and AFAIK, Kodak doesn't sell any products for the home darkroom. Everything is marked "for commercial and industrial use only". This must give them some liability protection, since all home darkroom workers are knaves and fools. As such, I prefer glacial acetic acid when I can get it, simply because I'm a cheap SOB and don't like to pay Kodak's prices for watered down chemistry. The only problem I can imagine is if someone managed to spill a lot in a small space- it would be overwhelming if you couldn't escape quickly. This is far less of a problem with todays plastic bottles. Way back, it came in brown glass bottles. Enough already. 28% is safer. Use whatever you have the knowledge to handle safely, even if it's only water. You guys both have tremendous knowledge that we can all benefit from. I've learned a huge amount from TFDC and private communications with Bill Troop. I've also learned a huge amount from public and private communications with Ron Mowrey. IMHO, they're both pretty nice guys, and generous with their accumulated wisdom. With appologies to any younger participants here, we're mostly old farts pursuing a dying craft. The combined brain trust here won't be around forever, and if there's anything of importance that we want to discuss or resolve, we should quit bickering and get to it.

rowland_mowrey · October 18, 2004

Anders, Conrad;

Thank you both.

End of discussion.

Ron Mowrey

bill_troop1 · October 18, 2004

>End of discussion.

Ron Mowrey<

Not without a postscript from Kodak's toxicology department, which can be reached 24 hours and is an invaluable resource.

Acetic acid greater than 20%: causes severe skin and eye burns; vapor is very irritating to eyes and respiratory system; may be fatal if swallowed.

Acetic Acid at 15-20%: causes skin and eye burn [note that 'severe' is no longer a characterization].

Acetic Acid at 5-15 %: can still cause eye burns but the skin characterization goes down from 'burn' to "irritation".

Acetic Acid at 1-5%: can cause eye irritation.

Ammonium thiocyanate has been shown to cause thyroid damage in humans.

bill_troop1 · October 18, 2004

and a couple of other footnotes:

> Another thing not generally known is that thiocyanates and thiourea are much more stable than hypo. Therefore it is theoretically possible to design a fix that does not decompose if you just leave out hypo and use thiourea and a thiocyanate. Wow, a fix that does not sulfurize.

Thiosulfate is only unstable in acid solution.

> read the MSDS as Lex suggests

but an MSDS usually contains the legally minimum information. More useful information will be obtained from a trained toxicologist at a poison control center. For example the MSDS does not have to tell you that exposure to ammonium thiocyanate may cause thyroid damage, but the toxicologist will be able to tell you that.

Finally, to anyone whose priority is saving time, the important thing is less the length of fixing time, than the length of the washing time. As long as the fixer contains any thiosulfate, there is only one way to dramatically reduce washing time: use it at alkaline pH.

May I suggest this simple test, Ron? Test washing times for your fixer as formulated; then comparison test washing times with your fixer reformulated to a pH around 9. You will find that washing times for both films and paper are approximately an order of magnitude less when you reformulate so that the fixer is alkaline. Have a look at Green and Rumens, J. Phot. Sci., 19:149-150 (1971). As the date indicates, this information has been publicly available for over 30 years. You will now have a fixer that both fixes rapidly _and_ washes rapidly.

To Ed: the Ilford rapid fixing system of circa 1980 was never accepted by Kodak, one reason being that it didn't work on Kodabromide paper. The theory depends on the fixer being able to clear the paper in under 10 seconds. As Ron has pointed out, there will be tremendous potential consistency problems at such short times. I do not remember anyone at Kodak making that explicit point to me, but I am certain that Ron is absolutely correct on this point. But that is only one problem. Papers have evolved since such that they can no longer be cleared in 10 seconds. Clearing times in fresh film-strength ammonium thiosulfate fixer are now more often greater than 30 seconds. Yet the Ilford system, considerably modified, still survives. I think we have to accept that Mason probably erred when he ascribed the system's initial success to short immersion times such that thiosulfate cannot bind to the paper fibres.

IF rapid, archival washing of films and papers is your goal, the only practical way to achieve it is through alkaline fixing. There is always the attractive possibility of eliminating thiosulfate altogether. But since W.E. Lee's disturbing papers showing that a very small residual amount of thiosulfate can have a stabilizing effect on b/w materials, there has been more reluctance to work with thiosulfate substitutes.

rowland_mowrey · October 19, 2004

Bill;

You won't stop, will you.

You said:

"We see here the problem with letting a lab boy out into the world. He doesn't have any experience of manufacturing, and no idea what companies have to do to protect their users. With all his decades of experience, he still doesn't understand why all responsible photographic companies, including Kodak, sell 28% rather than glacial acetic acid to photographers."

"And you still don't understand why photographic manufacturers don't like to let glacial acetic acid into photographers' hands?"

------

As noted above my myself and Terry Stedman, Eastman Kodak sells glacial acetic acid in 1 gallon and 6 x 1 gallon size quantities.

Kodak Professional Products, Kodak Tested Chemicals:

Cat # 146-2845 Kodak Glacial Acetic Acid (1-gal bottle)

Cat # 146-2852 Kodak Glacial Acetic Acid (6 1-gal jugs)

As noted by Patrick Gainer, he has accidentally aspirated some into his mouth and survived intact. As noted by Anders Brathe, acetic acid is a weak acid and is far weaker than sulfuric and far less damaging to human tissue than common lye sold in supermarkets.

I'm afraid that you did not understand Anders' post, as you probably don't have sufficient chemistry background. I suggest that you study up on pKsp, pKa, and heats of reaction and then you might fully understand some of what myself and others have been trying to get across here and in other posts. From the nature of your replies, you seem to completely misunderstand the difference between a strong and a weak acid, and in previous posts you have misunderstood the chemistry of pseudo halogens, and also the heats of reaction involved in development and acid base neutralization.

Did you ask the toxicology department at EK about any other chemicals? They will give you the litany of all of the possible horrible things that can happen to you with those chemicals as well. All photographic chemicals are toxic or harmful in some fashion or other. This is a given. Glutaraldehyde and other aldehydes are potentially as dangerous or more so than acetic acid. Go here:

http://www.ncchem.com/snftaas/crying_in_the_dark.htm

for details. You give formulas for such hardeners in your book, so you should be aware of this report.

I have worked with the toxicology department at EK several times when we were working with new chemicals, so I am quite familiar with their work and responsibility at EK.

Anders and Conrad have said something important here. People are tired of this relentless pursuit of person and not fact. They have presented facts.

Facts: Acetic acid is used in photography. It is a weak acid that is less toxic than some other chemicals but still has risk. It is sold by EK, the Photographers Formulary and other supply houses.

You like to ignore these facts and push to the forefront your own personal arguments over the facts that all chemicals are toxic, even sodium choride (table salt) if used improperly. And, in spite of this, the photographic supply companies still sell these chemicals. Whats more, even more toxic chemicals are sold in our supermarkets to less experienced people.

As for fixing and washing, non-hypo fixes have been known for years. Silver metal is stabilized by retention of small quantities of hypo. As Ctein also points this out in his article, there is lots of support for this observation besides the citations you give. As a matter of fact, many pros recommend some form of toning for ultimate stability of silver images. Therefore, it is possible to use hypo at the optimum pH and still have unstable images if the hypo is totally removed, as Ctein points out!

The use of any fixing agent at any pH with any good wash sufficient to remove silver complexes is effective as long as a suitable toner is used before drying. Alkaline hypo may not be the best. Alkaline hypo merely allows maximum swell for maxiumum diffusion outward which allows shorter wash times under some circumstances with some products.

As I pointed out before, and you mention, diffusion becomes important especially at lower temperatures. Swell affects diffusion, and the swell is determined by hardener in the coating, gelatin type, and a number of other factors including coating thickness. Therefore, wash effectiveness varies with product and manufacturer.

No simple statement can answer all of these factors. I believe in what Al Weber and Dave Vestal suggest. Ctein also recommends this. "Wash completely and tone for best B&W image stability."

Well, I had hoped to end this by not continuing the 'fray', but you seem determined to continue ad nauseum. I think by now that the evidence of continued sale of Glacial Acetic Acid by EK, and its sale by the Formulary should put paid to your contention that I quoted above and by the responses by others.

Ron Mowrey

bill_troop1 · October 19, 2004

>You won't stop, will you.

Well, if I've expressed myself so badly that you still don't get the point, I feel I must try harder.

>"And you still don't understand why photographic manufacturers don't like to let glacial acetic acid into photographers' hands?"

>------ As noted above my myself and Terry Stedman, Eastman Kodak sells glacial acetic acid in 1 gallon and 6 x 1 gallon size quantities.

But Ron: that's just the point: 1 gallon glacial acetic acid is intended not for _photographers_ but for _labs_. There's a century of manufacturing wisdom behind the practice of selling 28% acetic acid to _photographers_. Why argue with one of the industry's first real efforts to make the _photographer's_ darkroom safer? Leave the more dangerous chemicals to lab technicians who should know how to handle them.

>As noted by Patrick Gainer, he has accidentally aspirated some into his mouth and survived intact. As noted by Anders Brathe, acetic acid is a weak acid and is far weaker than sulfuric and far less damaging to human tissue than common lye sold in supermarkets.

Right. But Kodak's toxicologists believe (as they told me today) that if you swallow glacial acetic acid, you will likely die, because your oesophagal tract will have been burnt out. Who's right? Patrick, fortunately, didn't swallow. Shall we ask him to try it again? And while we're waiting to find out what happens, should we be encouraging people to treat glacial acetic acid as an aspirable chemical? Is that really in the best interests of the public?

>...you probably don't have sufficient chemistry background ... you seem to completely misunderstand the difference between a strong and a weak acid

Ron, I don't know how you get there just because I point out that the 28% acetic acid common sold to _photographers_ is much safer than the glacial acetic acid commonly sold to _labs_. Does Haist have an insufficient chemistry background because he spent a page pointing this out? Did Crabtree and Matthews have insufficient background because they too spent a page pointing this out?

>Did you ask the toxicology department at EK about any other chemicals?

No, because I thought we were discussing acetic acid.

>I have worked with the toxicology department at EK several times when we were working with new chemicals, so I am quite familiar with their work and responsibility at EK.

So give 'em a call!

>Alkaline hypo merely allows maximum swell for maxiumum diffusion outward which allows shorter wash times under some circumstances with some products.

That is deeply misrepresentative of the facts, Ron, because it does not account for the fact that, with alkaline fixing, you have an almost an order of magnitude less washing time. Alkaline post processing of acid-fixed prints doesn't get you anywhere near that level of success. Let me suggest again that you read Green and Rumens, J. Phot. Sci. 19:149-150 (1971). Or don't they have adequate chemistry background?

>No simple statement can answer all of these factors. I believe in what Al Weber and Dave Vestal suggest.

Then let me quote what David Vestal wrote about my TF-4 alkaline fixer in the March/April 1993 issue of Darkroom & Creative Camera Techniques, pp. 42-67:

"I ordered TF-4 for testing with some skepticism, mostly because of experiences with unhardened prints that were too soft physically to survive. However, the test measurements show that TF-4 is effective, and this time the print emulsion was not disturbingly soft [as it had been with Ilford's fixer]. It changes print processing and takes some getting used to, but it also shortens washing times and saves water. No acid stop bath is used with TF-4, and no washing aid."

Now Ron, if you'll put aside pride, and, as I suggest, reformulate your fixer to pH 8 or 9 -- I can suggest a suitable buffer system if you'd like -- I believe you will find that washing times are reduced by about an order of magnitude for film. The improvement for paper will be less, but will still be substantial. This simple alteration in your formula will cut down total processing time dramatically, and result in substantial savings of water. Put it this way: by supercharging ammonium thiosulfate, as you suggest, you can reduce fixing time from perhaps 2 minutes to 1. But only by alkalinizing the solution will you be able to cut down washing times in a really dramatic fashion. Film will be washed to archival levels in under 60 seconds; paper washing times will be reduced to about one third what they would be with the formula as presently published. It _is_ total processing time that we're interested in, here, isn't it?

Finally, have you tested for the paper softening Vestal was so concerned about in non-hardening paper fixers?

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