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Some thoughts on the use and management of salts in making Silver Halides.

Several patents refer to the use of thioethers (some being rather exotic crown structures) as "modifying the crystal habit" or "facilitating crystal growth". Would these be considered "solvents" of a type, or something more akin to "catalysts".

Just for fun, I looked up the pricing on a couple crown ethers and they are mighty pricey little beasts!
 
Ian, they are very expensive and once present, hard to turn off. They also cause a lot of fog if not handled properly. They are removed by diafiltration after they have done their work.

PE
 
 
Here we go again. Read my OP. I said much the same thing there.

And, just because it was used 100 years ago does not mean that it is good, better or best. It NH4X salts were not in common use for manufacturing or hobby purposes for nearly 75 years due to lack of any overwhelming advantage!

PE
 
75 years. Yup. That's just about perfect . Kodak materials were in their glory. In 1938, Katherine Hepburn and Cary Grant were "Bring Up Baby". One of my favorite movies, "It Happened One Night", was already four years old. Lovely films, both. My bridge across the Yaquina Bay was two years old. So was Hoover Dam. And the Golden Gate Bridge. The 1930's were an economic challenge for many people, but as far as technology, and art -- I'm proud to have my work harken back to those times.
 

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Thanks for taking the time to post this. Your first paragraphs answered a question I have pondered for too many years.

Jim
 
That sounds like non sequitur reasoning to me. Just because things were done someway 75 years ago doesn't mean we should do them that way today; 75 years ago, cars used leaded gas and had tube tires. Who wants those things today.
 
Well, I guess your attitude is consistent for a guy who has the brass to use "Prof Pixel" as a username on APUG.

You may want to consider being a bit less dogmatic when you're around Mark Osterman. His bread and butter, and that of George Eastman House, is all about preserving the old and historical. Some people actually want to do just that. Perhaps you could leave us to our personal tastes and goals.

http://www.thelightfarm.com/Map/Books/Osterman/MapTopic.htm
 
Mark's emulsion does not use any Ammonium Halide salts.

Denise, as stated in the OP, you can make Phosphorous by distilling rotted horse urine from a bed of sand. That is not done today for a number of obvious reasons, but the method works even today.

You can make emulsions with NH4X salts, but it is not necessary. It adds nothing to your work except the label "exotic" and it takes up space on your lab shelves and in your refrigerator. Yes, you can stock all 7 major Halide salts, but I can make do with just 3. It saves money as well.

So, why use it? IDK. None of my co-workers used it. As stated above, they did use (NH4)2SO4 and NH4OH for making emulsions and to much better effect. See those electron micrographs again!!

PE
 
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OK. One more try. Any more and I'll have to go find a giff about beating a dead horse.

You ask "why?". It is a far more beautiful emulsion than the identical one with KBr (to me, and who else matters?)

It allows the use of much more vigorous developers, so it is effectively faster.

I made a full ammoniacal emulsion today. The one that will allow me to shoot my 120 rangefinder handheld at a festival this weekend. But, you see, I have excellent ventilation. It wouldn't be so simple if I didn't. Many people are unable to make ammoniacal emulsions. That doesn't make them second class citizens. They should have options. I would never think of telling people they shouldn't be making your emulsions. Actually, I'm not sure exactly what "your" emulsions are. Never see pictures.

I only stock two bromides. Potassium and ammonium. Does that mean I "win" that particular contest?

I'm sure you'll come back again, swinging from a different corner of your box, but now it's my turn to ask "why?" I'll leave your answer unchallenged.
 

I've been following this thread out of curiosity since PE is "dropping the knowledge" but it's still a little far advance for me most the time, but I have a simpleton question.

You said it allows for more vigorous agitation, but wouldn't that also make for really grainy images? I know that's not really the question here but I guess it seems sort of counterproductive to make an emulsion that you can only make fast by making it severely grainy. unless you are specifically going for that look.

Please forgive me if I'm totally confused here.


Sent w/ iPhone using Tapatalk
 
Hi Stone,

The fact that you are totally confused is sad beyond expression. It's certainly not your fault. Making emulsions (at the home darkroom level) is simpler than baking a cake. It is nearly tragic that it is not allowed to be simple here.

I didn't mean vigorous agitation. Rather, more vigorous developer formulas. The best I can respond is to ask you to read three short pages, starting here: http://thelightfarm.com/cgi-bin/htmltutgen.py?content=15Jun2013
 
Denise, there are people here that make high speed emulsions with absolutely no Ammonia whatsoever either. So, just about anything is possible. It is what you must do vs what is optional that is being described (and tested) here in this thread.

It is certainly easy to make an emulsion. I use NaBr, NaCl and KI as my 3 salts. I use NH4OH as my source of Ammonia if desired. I get good speed and tone. You have seen my prints and plates personally snf do have my students. So, if what you do makes you happy, then do it. I do what seems to make my students happy and it also makes me happy.

Best wishes.

PE
 
This one?
 

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Thanks, now I see what you mean.

However it was a little hurtful in how it came out. Please realize I don't have access to a darkroom and cannot set one up here, I can only use a dark bag for now.

Someday I'll have access to more.


Sent w/ iPhone using Tapatalk
 
Stone,

I think you mean I was hurtful to you (??) If so, please believe it was not my intent. I was answering the best I could, with the utmost respect for your quest for knowledge.

Tom,
Great giff.
 
Sheesh! It's been said a thousand times before: making a simple emulsion is NOT DIFFICULT. A simple chloride paper can be made and coated in an hour.

Making a repeatable, higher-speed emulsion, spectrally sensitized, with a controlled response, good keeping etc., IS NOT SIMPLE.

I don't recall anybody saying that emulsions cannot be made with xxx or yyy, but rather that over the past 75+ many advances have been made.
 
FWIW, I think Denise's comment was that it was sad that the subject of the thread seemed to have been made more confusing by the contents of this thread.

Whereas Stone thought she meant that Stone was sad and confused.

While Stone has been known to have been confused from time to time , I don't think he seems at all sad and confused.

(I hope the emoticons show up on Stone's phone).
 

Lol! Emoticons work

Also, yes you understood but now I understand I read her comment wrong.

Ok all clear now.

What makes it hard is simply that I just don't have access to a dark room, I only have a light proof changing bag and a developing tank, hard to make emulsions inside of a developing tank.

Ironically my iPhone dictation heard me say that "It's hard to make EMOTIONS inside of developing tank", hehe


Sent w/ iPhone using Tapatalk
 

Denise you forget the rise of the third reich Agfa color and Kodakchrome as well as the beginning of the second world war
But I agree in terms of Art, product design especially cars, Hollywood musicals and production design and some Architecture the 1930's were top. The best looking Kodak emulsion imo is also from the 1930's Kodak Super Sensitive Panachromatic, what a beauty and last but not least Kodak was still able to create some great ads.
 
MDR.

I imagine all artists carry a vision in their head and heart of how they want their art to look. 1938 was well before my time, but looking at family photos from then are some of my first memories. Who knows all the influences that get us where we are today, or where we'll be tomorrow. Or the intangible aspects of our goals as artists. My intangibles include a love of history and the joy of working with my hands. I revere the concept of mastering a process. I love everything about darkrooms. Don't love computers.

Photography has had a thorny problem from the beginning -- materials. Always changing. Always "improving". I suppose if one were to buy into the 'latest and greatest' mentality, you could get what you want from your smart phone and Instagram . There are certainly enough people who will argue that because we can, we should. But, I'm stuck with my personal intangibles. And, in all honesty, I don't think there is art without the personal.
 
Some back information on emulsion making

In order to try and clarify some points here, I will give some "history" of emulsion making.

Period before 1945:

Emulsion making in the public press was empirical and lots of information was left out of published formulas. Each "researcher" wanted to make a major coup in the field.

At this time, there was only active gelatin for making, and it came in 3 or more forms. Generally, these were ranked as soft, medium and hard. This referred to contrast or sometimes speed. Each gelatin company manufactured a different "trio" of these and each "researcher" preferred a different set. Very often, the type of gelatin was omitted in a formula for secrecy or to allow other dabblers some leeway in what to use. Also omitted were addition times and temperatures, two critical issues that were deep dark secrets.

Commercial emulsions were kept secret. Nothing was published about them.

However, some give a break point in the time line when Sheppard of EK published his monumental work on Sulfur sensitization. Since formulas and the new inactive gelatins were not readily available, the break (in my mind) came in about 1945.

This early period was characterized by a lot of public "art" or "beauty" emulsions with no fully published formulas and which used some pretty exotic methods or chemicals to give them their "glow". These quoted comments often came from the empirical workers trying to attract adherents to their school of photography.

Period: 1945 to about 1970

During this time, few empirical workers survived. This was the age of big photo companies. But, OTOH, since the Agfa formulas had become public property, almost everyone but Kodak used them. This includes EFKE, ORWO, FUJI and a host of others. It was characterized by extreme secrecy at EK with a "Silver Curtain" over all emulsion work. So, there were roughly 4 families of products "Agfa type", Kodak, Dupont and Ilford. Gradually, Fuji and Konica began to diverge with some excellent original work leaving many others with the "Agfa" type formulas.

Agfa formulas, as published gave addition times and temperatures along with final conductivity after wash and gelatin time. They were obfuscated by either poor translation or outright misleading statements by the German scientists and engineers and thus you see many errors where they are reproduced.

This was the big era of Cadmium, Lead and Mercury.

Period: About 1970 to present

This era was still shrouded in secrecy, but the big 3 (Kodak, Ilford and Fuji) had moved far from any Agfa type formulations (Not that I could every find any use of the agfa formulas at EK). All heavy metals were removed and either the products died or the metals were replaced by special organic chemicals.

This era was marked by the use of computerized makes and very complex and long precipitations. I have seen formulas that took up to 3 hours. Oh, I did one AAMOF! This was a 9% Iodide emulsion for very high speed.


Now - MY GOAL.

1. To show the early method along with its faults and false trails. Some claim that there are no false trails, but there are! Believe me.

2. To use the middle period with some EK nohow to get ISO 25 - 200 ortho and pan emulsions that are simple enough to make in a home darkroom. With my help, some of my students are nearing the mid range. But, others claim that I am wrong in my approach and am making it too hard. Well, too hard is in the eye of the beholder or what one wants to achieve. I hear no complaints (other than the cost of AgNO3) from those getting ISO 100 emulsions.

3. To document the recent trends. I do not urge or suggest anyone get into this unless they are really interested and dedicated. I've been successful so far. No takers. BUT, I have a PM mail box stuffed with messages from those with questions about items 2 and 3 here. So...

Anyhow, the varying opinions on what is "right", "proper" or "wrong" in this entire post have lead to many hours of argument on-line and many pages of deleted posts.

I offer that Ian is right. There are no wrong or right answers, but with nearly 40 years doing this stuff, you might conceded that I am right more often than wrong. Now, this may be the wrong way to end such a post. Maybe I should never have made it at all. But, for those interested, the book gives several more pages of this stuff with diagrams and etc.

I am becoming more and more discouraged about this all. Of what use is is if just about every post I make on my own expert field of endeavor is questioned!

Best wishes to all.

PE
 
Denise, 1938 was the start of our modern films, Kodak lagged a year or so behind Ilford and Agfa, Ilford already had their Fine Grain Panchromatic Film and Hypersensitive Panchromatic emulsions. the first in the series that became the films we know today FP4+ & HP5+. Kodaks equivalents Pan-X, Plus-X, Super-X & Tri-X were 1939/40.

I'm not sure if Tri-X was made by EK in the US at that time but it was made in the UK by Kodak Ltd and at their new coating plant in Hungary. I have the data sheets and availability in a Kodak Ltd Professional Catalogue. The Hungarian plant was taken over by the Nazis and later became Forte and the Super-X and Tri-X emulsions evolved in a different way - the last versions were known as Fortepan200 & 400 (also Bergger 200 & 400).

Ilford introduced FP2 and HP2 around the same time as Kodak's new modern range. But the major break through after that was the thin coated emulsions from Dr C. Schleussner Fotowerke GmbH which were streeets ahead in terms of fine grain and sharpness in the early 1950's but most of us only know these Adox brand emulsions from the period after Dupont (who took the company over) had sold the machinery and licensed the emulsion manufacture to EFKE in Zagreb.

It took other companies around a decade to get close, FP4 was for a long time thought to be the best all-round film available and it was years later that Tmax100 surpassed it. But then the effective EI of EFKE KB/R/PL 14(DIN) later called 25 (ASA/ISO its Tungsten speed) was the same as Kodak's 50EI emulsion called Tmax 100 in daylight - only after Kodak had the ASA part of the ISO tests changed as the film failed the older tests !!!!! A Kodak consultant stated this prior to final release (a member here), and Kodak's own literature said it needed to be exposed at 50EI if you wanted details in the shadows !

Another thing that's now conveniently forgotten was Kodak couldn't make consistent emulsions up until the the introduction of T grain films, a technology from Kodak Ltd in Harrow.

When I first used Tri-X the Kodak developer data-sheets had different suggested ISO's and development times for US, Canadian & British coated film, and Ektachrome Professional had a suggested ASA on the box which could vary batch by batch. Fujichrome was so consistent and their E4 films so much better.

There's a need for openness and not Dogma in these posts.

Ian
 
Denise I am a production designer, art historian and photographer by education and a big fan of 1920's and 1930's production design so I am a bit biased towards a certain aesthetic. Agfa Isopan is another great emulsion and was considered by many to be superior to Kodak products of the same time.

I believe that there was certain philosophy behind every film company Agfa parent company and their chemical production influenced the way emulsions were made at Agfa, Kodak was pretty much independent and bought a lot of their knowledge. Fuji as a japanese company was aided by Agfa during the war some of their early emulsions reflect that influence but they soon seemed to have found their own philosophy. Dr. Schleussner was driven by innovation he had to constantly innovate or he would have perished much sooner. Kodak was a lot bigger than Ilford, Schleussner and Fuji so they didn't have the need for constant innovation.
 
I am glad that there is one of the actual technicians of the film technology giving of himself in this point of life to share the knowledge straight from the horse's mouth. Were it not for that, as these people pass from us, the entire technology would fall into the hands of revisionists. Speaking as an offset printer, a kin trade of photography's, I would not have this roof over my head most likely without the research and distribution of the materials, supplies, and knowledge of these engineers. Thank you.
 
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