Is food grade chemistry OK for use for photography?

Ian Grant · May 17, 2009

Ray Rogers said:
Perhaps... a better idea would be to pass this discussion on to 20 mule tech team and encourage them to certify their product... they could afford to increase their sales I would guess....

I used to buy "20 Mule Team" Borax from Consolidated Borax (UK) by the metric Tonne, usually 4 or 8 at a time, palleted in 1 tonne batches in 50kg (later 25kg) bags.

This was Technical grade and worked fine for photographic uses, Rio Tinto sold off the "20 Mule Team" branded house-hold product line but it's unlikely it's an inferior grade.

Ian

sanking · May 17, 2009

I just looked through several dozen bottles of chemicals on my shelf. This includes chemicals bottled by Kodak, Edwal, Bryant Laboratories, Artcraft, Formulary, Lauder Chemicals, and one or two others you never heard of.

I found only one that was labeled photograhic grade, and that was a bottle of sodium sulfite packaged by Edwal. The Kodak bottles were labeled "Photograhic or Technical Quality", chemistry from the Formulary is labeled "Technical Application". Lauder also labeled chemistry as "Technical Application." Bryant Laboratory used the term "Technical Quality". Artcraft bottles do not indicate type of quality.

So from a strictly practical consideration the use of "photograhic quality" would seem to be rather rare based on my own supply of chemistry, which is quite extensive.

Sandy King

Ian Grant · May 17, 2009

LFA Mason in his book "Photographic Processing Chemistry" lists the British Standards Institute specifications for some of the most common photographic chemicals. The BS standards are simila to the old ANSI/ASA standards which allong with DIN became part of the International ISO system

It's likely that only chemicals manufacture specifically for photographic use would be marked Photographic Grade as other chemicals have a multitude of other industrial uses.

Borax for instance must have an Assay of 99.5%, maximum Fe of 0.003%, maximum Heavy metals 0.002%. It's unlikely that many chemicals used commercially would have a purity higher than Technical Grade as the cost factor of using Laboratory reagents is quite significant.

Ian

Photo Engineer · May 17, 2009

Borax is not the only chemical at issue here, others are as well. Almost all bulk suppliers make their products available in several grades and Kodak among others buys from the same source as many other photo material manufacturers.

Ian and Kirk are correct. Specifications exist in the form of old ANSI and new ISO standards for every chemical we use and if Technical grade is equal to Photo grade then they are equal, but they may not be equal to Food grade. I have given the common differences in previous posts and they mainly center around anti caking agents, heavy metals, and insoluble matter.

The issue still remains that if, say, bulk purchases of hypo, carbonate and borax dwindle at Artcraft, B&H, and the Photographers Formulary, where will you get the more important chemistry? Where will the HQ, Metol, Dimezone and etc. come from?

That question should remain paramount.

PE

alanrockwood · May 17, 2009

I found the following link to a document from Eastman chemical that discusses requirements for food grade products.

http://www.eastman.com/NR/rdonlyres/3ED41B12-2C74-4066-B26B-7AB4CF7FAF6B/0/Z21.pdf

Interestingly, according to this document food grade products are generally of higher purity than industrial grade products (item #3 in the document.)

Of course, "food grade" doesn't apply to many products of photographic interest, ascorbic acid being a possible exception, but it is of some interest anyway because the term "food grade" has so often been mentioned in conjunction with this discussion.

Ian Grant · May 17, 2009

The whole point about Food grade chemicals, and one that Ron (PE) has highlighted, is they can be legitimately adulterated with additives by the time they are re-packaged and sold to the Public.

Ian

gainer · May 17, 2009

Please, guts. There is no food grade of borax. Borax comes in Technical, European Pharmacopeia, National Formulary and Special Quality. If you called Dial and asked for food grade borax, I would hope you would be counseled not to put it in your mouth. What are we argiung about here? How in the name of common sense, or even uncommon nonsense, can my suggestion that a standard solution is a better way to keep and measure borax than the dry crystals or powder. The amount of sodium tetraborate in a gram of the dry form will vary with the humidity as the ratio of pentahydrate to decahydrate changes, even while it is being weighed. Whether I purchase the purest possible borax or use laundry borax, The best way to keep it for accuracy of measurement is in a standard solution. If the laundry borax is made into a saturated solution with boiling water, the solution that is decanted will have a higher percentage of impurities than remains in the precipitate. That may be used for the laundry and the precipitated borax dissolved again in hot water. Can we deny that the second saturated solution after cooling will have less soluble impurity than the first? The chemists who are supposed to be the masters of precise and accurate measurement of purest chemicals seem to have forgotten that, no matter how pure the borax is to start, the second recryatallization will produce a cleaner product.

Read again what Sandy said about the chemicals on his shelves. Go ahead and buy what you believe to be Photo Grade chemicals, but if you want to be sure of pure borax, there is a simple way to do so. It will not be used by most because it takes considerable time.

gainer · May 17, 2009

Errata: "guts" should have been "guys".

alanrockwood · May 17, 2009

alanrockwood said:
...Of course, "food grade" doesn't apply to many products of photographic interest, ascorbic acid being a possible exception...

Oops, how could I have forgotten about some other food grade products of photographic interest, such as sodium bicarbonate.

alanrockwood · May 17, 2009

alanrockwood said:
...Interestingly, according to this document food grade products are generally of higher purity than industrial grade products (item #3 in the document.)...

Also of note, the Eastman document compares food grade to "industrial grade" products. I am not sure if industrial grade is appropriate for photographic applications. However, the point remains that food grade products are generally of pretty good purity.

alanrockwood · May 17, 2009

Patrick's point that recrystallization can be used to purify a chemical is correct. It is a standard technique taught in college chemistry laboratory classes.

One could argue whether it is worth the effort, but it is definitely a legitimate way to purify a chemical.

sanking · May 17, 2009

But that is an entirely different issue, and not one raised by the OP.

As long as I can remember photographers have talked about grocery store chemistry that can be used in the darkroom. But as best I can tell this has had little or no impact on the ability of photochemical suppliers to compete in this market. I personally have long been aware of the grocery store possibilities but would much rather just buy sodium metaborate than buy and then mix mule team borax with red devil lye. And the difference in price is usually not that great, in fact the grocery store prices are often more than what you would pay for the same chemical from one of the photochemical suppliers. I am fairly positive that the great majority of photographers who mix their own darkroom developers, fixers, toners, etc. feel the same way, especially if they are more highly involved in print making than in experimentation.

On the other hand I will not hesitate to use a substitute product if it is clearly just as good and can be purchased for a lot less. For example, the gelatin I use to make carbon tissue is purchased from a food supply outlet and costs about 1/5 per pound of what it would cost me to buy photo quality gelatin. And for my purpose it is every bit as good. This gelatin may not be good for making silver emulsions, and I don't recommend it for that purpose. But for making carbon tissue it serves my needs every bit as well (in fact, even better) as the much more expensive photo gelatin I could buy directly from Kind & Knox, and it costs a lot less.

Sandy King

Photo Engineer said:
The issue still remains that if, say, bulk purchases of hypo, carbonate and borax dwindle at Artcraft, B&H, and the Photographers Formulary, where will you get the more important chemistry? Where will the HQ, Metol, Dimezone and etc. come from?

That question should remain paramount.

PE

gainer · May 17, 2009

Here's a novel thought. Instead of trying to prove me wrong, why don't you resident chemists analyze the borax you have been buying from the sources you fear will die if you don't, just to see if that borax is in fact significantly different from what I have in my laundry room or from that which I can get in the second stage of recrystallization? That might put a little different focus, to use a photographic term, on our discussion.

Photo Engineer · May 17, 2009

Patrick;

I answered this very question in another post the last time you posed it about 2 pages ago.

PE

alanrockwood · May 17, 2009

Just out of curiosity, does anyone know of a supplier of photo grade cafenol?

sanking · May 17, 2009

No, but according to Anchell and Troop (The Film Developing Cookbook, p. 25) pyrocatechin (also known was catechol and pyrocatechol, and other) is a toxic benzene said to be a constituent of human urine. Perhpas some of our resident photo chemist gurus would find a way to convert urine to photochemical grade pyrocatchine. Most human bodies produce an abundance of the toxic benzene on a daily basis so there should be no shortage of the chemical.

Strikes me as very environmentally friendly way to produce pure reducer for photographic use. And in the long run, perhaps a better use of the time of the chemist gurus than the rather toxic exchange we have seen here.

Sandy

alanrockwood said:
Just out of curiosity, does anyone know of a supplier of photo grade cafenol?

gainer · May 17, 2009

Photo Engineer said:
Patrick;

I answered this very question in another post the last time you posed it about 2 pages ago.

PE

I must have missed the part where you actually did the tests and showed that the borax you got from the Formulary actually met the specs of the ANSI for photography chemicals, while laundry borax did not. There are required an assay, a test for iron, a test for carbonate, a test for reaction to ammoniacal silver nitrate, and a test for appearance. If you did these tests, you did not report the results to us.

wogster · May 17, 2009

Photo Engineer said:
You must have missed several of my posts.

I agree with you to an extent in that you can run simple tests with this chemistry, but in some cases, you can run into a "gotcha" with cheap chemistry and ruin your photos. You may not even be aware of the source of the problem as the developer or fixer may have been ok 9 times before.

See my analogy to the speeder. Someday you will be nailed by your chemistry if it is not up to par.

PE

Maybe I wasn't quite clear here, I mix up a litre of D76, I use it on a test roll, or some crap I shot that I don't really care about, it works fine, it's now a known good batch, and I can use it for other films that I do care about. Next batch I make, again I use a non critical roll first, know it's good and continue on. You may even be okay until you run out of something, so you buy some more and do a test roll first.

Mind you, the whole argument is moot to me anyway. Maybe if I had Mr. Gainers experience at it, I might think differently, but if I want D76, I can bicycle over to the photo shop in half an hour buy a bag for $4 so why the heck go through the hassle of getting a variety of stuff together from various places and doing a lot of work that the folks at Kodak or Ilford have already done in a nice convenient package. Now If I wanted a developer that I can't buy pre-mixed at the photo store, that would be different, but D76/ID11 works well for me, because. I like to reserve monkeying with stuff for the printing stage. I have taken the same negative and printed it radically differently at different times, depending on my mood and disposition, so I intentionally keep the negatives pretty mundane and uniform, to give me the most flexibility at printing time, so I tend to stick to D76 or ID11 depending on which is cheaper.

Photo Engineer · May 17, 2009

gainer said:
I must have missed the part where you actually did the tests and showed that the borax you got from the Formulary actually met the specs of the ANSI for photography chemicals, while laundry borax did not. There are required an assay, a test for iron, a test for carbonate, a test for reaction to ammoniacal silver nitrate, and a test for appearance. If you did these tests, you did not report the results to us.

Patrick;

Many years ago, a fellow named Dean "invented" a super space drive to power space ships. It was all the rage among amateur or would be aeronautical engineers in the 60s or 70s and got a lot of publicity in the cheap press.

Interestingly enough, no aeronautical engineers seemed to want to jump on the bandwagon and either prove or disprove it, as reputable engineers knew better than trying to get something for nothing, kind of like perpetual motion.

The drive eventually faded from sight as no one could really get it to work the way the originator claimed although small scale devices did lift small weights if properly constructed (IIRC).

Well, I am in the same position and I reiterate what I said before. Why should I be on the defensive to prove the contentions of an amateur. I took the courses and did the work and at EK we were taught some basic facts about photographic chemistry, but were not forced to waste a lot of our time on things that are rather basic to chemistry and photography.

What you suggest may work 9 out of 10 times or 1 out of 10 times. It is a matter of statistics. I just don't care to go over ground I worked through as part of my education and training over 30 years ago.

It is up to you to prove that your contentions work, and do so reliably with statistically high certainty looking for the problems that a photo engineer would look for based on his background and training.

PE

gainer · May 17, 2009

There is a non sequitur here somewhere. You seem to be saying that because you are a trained and experienced photographic chemist, you know without testing that what you buy is better than what I buy. Did you even ask your supplier for the specifications of what you buy? Does it come from one of these retailers whom you are trying to save from the vicious and ignorant Gadget Gainer. Bah! Humbug!

We had one of those inventors pestering one of our guys at Langley. I don't remember his name, but it wasn't Dean. This guy's idea was like putting a wind driven generator atop an automobile. All you had to do was get it started, and you could drive all day on the electricity generated by your forward motion. Certainly, there are some things that are known to be impossible just from what we know of physics and chemistry. When we do know that borax is easily produced in a number of different grades of purity, it would be well if we could test to make sure we are not being supplied a grade that is inferior to what we paid for. I am quite surprised that you, a trained profesional chemist, would be so averse to using a standardized solution, especially for borax which has two widely different molecular weights which become one in solution, and which is so easily purified by crystallization. I am even more surprised that you refuse to back up your assertions by specific chemical tests. If one of your suppliers of borax sent you laundry grade, how long would it take you to find out about it?

alanrockwood · May 18, 2009

If I may weigh in again, this time regarding testing, experimentation is the ultimate test. My graduate school mentor, a theoretical chemist, used to say "theory proposes, experiment disposes."

From that point of view, much of the discussion in this thread is speculation with a relatively small (albeit non-zero) component of science.

With regard to experimentation, the ultimate test is not how pure the chemical is but whether the grade of the chemical in question is "fit for purpose." Therefore, the true test is functional testing, not purity testing.

Purity testing may play a role in the bigger picture. Purity testing, together with other appropriate experimentation, may help the researcher identify which impurities may adversely affect function. The testing itself will not tell us whether an impurity may adversely affect function, but it can be one component of the larger research plan.

In addition, purity testing can be one component of a Quality Assurance/Quality Control program, i.e. a way to make sure that product quality is and continues to be adequate for the task.

However, let me reiterate, it is only functional testing that can truly answer whether a certain grade of chemical is fit for purpose. Purity testing is only an adjunct activity. It is not even a necessary activity, provided that one could assume that the quality of a raw material does not change in quality over time. (A sometimes dangerous assumption, but I will reserve that discussion for another time.)

Therefore, it is only functional testing that will tell us whether food grade chemicals are adequate for photographic applications. All pronouncements in the absence of such testing are speculation. Perhaps informed speculation in some cases, but nevertheless unproven statements.

There may be good reasons for someone to decide not to perform the tests needed to prove whether food grade chemicals are adequate for photographic applications, but those good reasons to forgo testing do not constitute a substitute for actual testing.

I'm not sure I am making that last point clearly enough, so let me put things another way. I would not blame anyone for refusing to perform the testing required to answer the question. Furthermore, I would not bar anyone from expressing an opinion on the probable outcome of such a test. (An opinion on the probable outcome would be characterized as a hypothesis.) However, in the absence of the actual testing, the opinion, even an opinion from an expert, remains unsubstantiated... perhaps fodder for interesting conversation and debate, and maybe even useful for rough guidance in the absence of established results, but unsubstantiated nevertheless.

I'll give Patrick this much. He is willing to experiment. I have not followed all his work, and I will not judge the overall quality of his work in this post, but at least he is one who seems to be willing to do experiments. This is not to say that he always takes on the challenge of proof by experimentation, but on the whole he seems to be of an experimentalists frame of mind. On the other hand, it seems to me that Patrick sometimes has a tendency to reject criticism if his work too quickly.

I'll say this about PE. He is a highly experienced and knowledgeable expert whose opinion needs to be carefully listened to. However, at times PE also seems unwilling to do the experiments needed to back some of his claims made in posts, and may at times be overly sure of his opinions. As I said, there are often good reasons for declining to do experiments. It can sometimes be difficult, expensive, lengthy, and unrewarding work. However, expert opinion in the absence of experimental verification remain interesting (possibly even useful) speculation, but speculation nevertheless.

One other thing is clear. Neither Patrick nor PE seem to be able to read, integrate, and carefully consider all of what the other person is saying. That is a fancy way of saying that they don't listen to each other very well. This much is clear from even a cursory reading of the running battles they have been having with each other. This seems obvious to me as a an observer with no ax to grind.

There are too many instances where factual matters seem to have been ignored by opponents later posts. When I say "factual matters" I am not referring just to scientific issues, but mainly to historical fact, i.e. who said what, when did they say it, etc.

I actually enjoy part of what comes out in the exchanges between Patrick and PE. However, at times it also becomes almost too painful to watch, especially when it deteriorates into tit for tat exchanges.

wogster · May 18, 2009

alanrockwood said:
If I may weigh in again, this time regarding testing, experimentation is the ultimate test. My graduate school mentor, a theoretical chemist, used to say "theory proposes, experiment disposes."

From that point of view, much of the discussion in this thread is speculation with a relatively small (albeit non-zero) component of science.

With regard to experimentation, the ultimate test is not how pure the chemical is but whether the grade of the chemical in question is "fit for purpose." Therefore, the true test is functional testing, not purity testing.

Purity testing may play a role in the bigger picture. Purity testing, together with other appropriate experimentation, may help the researcher identify which impurities may adversely affect function. The testing itself will not tell us whether an impurity may adversely affect function, but it can be one component of the larger research plan.

In addition, purity testing can be one component of a Quality Assurance/Quality Control program, i.e. a way to make sure that product quality is and continues to be adequate for the task.

However, let me reiterate, it is only functional testing that can truly answer whether a certain grade of chemical is fit for purpose. Purity testing is only an adjunct activity. It is not even a necessary activity, provided that one could assume that the quality of a raw material does not change in quality over time. (A sometimes dangerous assumption, but I will reserve that discussion for another time.)

Therefore, it is only functional testing that will tell us whether food grade chemicals are adequate for photographic applications. All pronouncements in the absence of such testing are speculation. Perhaps informed speculation in some cases, but nevertheless unproven statements.

There may be good reasons for someone to decide not to perform the tests needed to prove whether food grade chemicals are adequate for photographic applications, but those good reasons to forgo testing do not constitute a substitute for actual testing.

I'm not sure I am making that last point clearly enough, so let me put things another way. I would not blame anyone for refusing to perform the testing required to answer the question. Furthermore, I would not bar anyone from expressing an opinion on the probable outcome of such a test. (An opinion on the probable outcome would be characterized as a hypothesis.) However, in the absence of the actual testing, the opinion, even an opinion from an expert, remains unsubstantiated... perhaps fodder for interesting conversation and debate, and maybe even useful for rough guidance in the absence of established results, but unsubstantiated nevertheless.

I'll give Patrick this much. He is willing to experiment. I have not followed all his work, and I will not judge the overall quality of his work in this post, but at least he is one who seems to be willing to do experiments. This is not to say that he always takes on the challenge of proof by experimentation, but on the whole he seems to be of an experimentalists frame of mind. On the other hand, it seems to me that Patrick sometimes has a tendency to reject criticism if his work too quickly.

I'll say this about PE. He is a highly experienced and knowledgeable expert whose opinion needs to be carefully listened to. However, at times PE also seems unwilling to do the experiments needed to back some of his claims made in posts, and may at times be overly sure of his opinions. As I said, there are often good reasons for declining to do experiments. It can sometimes be difficult, expensive, lengthy, and unrewarding work. However, expert opinion in the absence of experimental verification remain interesting (possibly even useful) speculation, but speculation nevertheless.

One other thing is clear. Neither Patrick nor PE seem to be able to read, integrate, and carefully consider all of what the other person is saying. That is a fancy way of saying that they don't listen to each other very well. This much is clear from even a cursory reading of the running battles they have been having with each other. This seems obvious to me as a an observer with no ax to grind.

There are too many instances where factual matters seem to have been ignored by opponents later posts. When I say "factual matters" I am not referring just to scientific issues, but mainly to historical fact, i.e. who said what, when did they say it, etc.

I actually enjoy part of what comes out in the exchanges between Patrick and PE. However, at times it also becomes almost too painful to watch, especially when it deteriorates into tit for tat exchanges.

This is well put Alan.

Photo Engineer · May 18, 2009

Alan;

It is well put, but not complete.

I have run many of those tests years ago or have seen the results of tests run by others. My time is limited as is my budget and therefore doing the dozens of experiments needed takes time away from the book, the emulsions and other work which is more important.

Therefore your judgment, while superficially reasonable, is not accurate. If I had an unlimited budget and a few lab assistants, I would be happy to do the work. But to me, it would be a tedious repeat of things I did years ago or saw done years ago, or was told "read the reports, it isn't worth repeating when it is so obvious and logical".

Now, if it comes to a vote , which do you want? Emulsion work and a textbook with all of the experiments and data, or my chasing a will of the wisp that I have seen, caught and identified over 30 years ago?

Remember, I am only trying to alert you to a potential for failure. I feel like the guys trying to tell NASA that the "O" rings on the Shuttle vehicle were weak at low temperature. Patrick has made a proposal which is new and novel. He is now obligated to prove it works. I am only obligated to give my opinion based on experience and chemical facts.

Now, as a chemist Alan, please consider what I have said in my posts and tell me if they are illogical or unreasonable from a chemical or physical POV. You have seemed to avoid that. I have read all of Patrick's posts in detail and find that he states a fact from an experiment without a reference or check experiment for comparison. He also uses the phrase "they look just fine". The data I have seen comes from things like photomicrographs which show trapped particles.

You may wish to consider this previous paragraph in your thoughts.

PE

Ray Rogers · May 18, 2009

Photo Engineer said:
Alan;

It is well put, but not complete.

I have run many of those tests years ago... The data I have seen comes from things like photomicrographs which show trapped particles.PE

Using which brand and grade of borax?
Are you saying Kodak actually had you test 20 mule brand borax?

I think your position is weak unless you can obtain analytical data on both,
and point out in specfic detail what is in excess of acceptable amounts.

I do not think you need to do original work... nor is it necesssary that you do the leg work,
a well written letter to a small handful of people should turn up the needed data.

As for lab assistants, the world is at your fingertips!

Photo Engineer said:
Remember, I am only trying to alert you to a potential for failure

I think the problem is that the only method you have given for people to avoid that potential,
is to blndly buy something that you have not sufficiently characterized....

What is missing is the actual data so that people can make up their own mind.
It is nice to have someone to trust, but sometimes people just have to make up their own minds and do not want to blindly take the advice of others... Kodak, PF, AC, BS or anyone else.

If all you want is to alert people of the potential for failure,
I think you are spending way to much time on this!

Kodak had a much smarter approach to this giving this warning
(rough quote from memory):

"Other manufacturers products may be substituted,
but equivalent results may not be obtained"

gainer · May 18, 2009

Let us go about this by a different path. Let's say you never heard of me. I need some borax good enough for photographic work, that will not do the bad things we are told might be done by laundry borax. I live 100 miles in any direction from a retail supplier of photochemicals. I post a request for advice. Is there any way I can get the stuff I need by doing something to my laundry borax? What is in laundry borax that does not meet the specs for photo grade? I know that the borax I need should have no more than 0.002% heavy metals, 0.003% iron, and that carbonate, reaction to Ammoniacal Silver Nitrate, and appearance of solution must pass certain tests. Who will respond any better than I did with my borax project?

Is food grade chemistry OK for use for photography?

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