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Our Recent Silver Bromide Gelatin Emulsion Workshop

Addition times from 1' to 15' are possible for this emulsion, but difficult o do by hand. The contrast will be quite low at 15' if everything behaves as normal, and the speed will probably move about 1 stop, but it may appear to slow down due to the loss in contrast. Here is a typical curve of the usual senitometric change with addition times from 8 - 14 minutes with a given emulsion. You can see what happens to speed and density as well as contrast.

PE
 

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Ron,

A longer addition time would produce a lower contrast, I understand that, but why would it increase speed? Is it because the grains formed first would have more opportunity to grow larger at the expense of the smaller grains than in a more monodisperse emulsion?

-- Jason
 
You get more speed for the same reason that you get lower contrast. You get a broader size / frequency distribution. There are more fine grains and more coarse grains. With a very fast addition, you get grains that are more nearly alike and they are smaller.

PE
 

andy

if you go to thelightfarm.com
look under formulas
there is a very simple sea water emulsion
that the maker uses to coat plates
and it only has a few ingredients ..
no crazy chemicals, just silver nitrate
seawater/ salt+water and gelatin ( from what i remember )
salt prints were just saltwater and silver nitrate too, so this is just
a little different ... if a 20year old college student with NO EXPERIENCE
and a booklet from 1904 could do something like his at 2-3am ( in the 1980s )
i think it would be a piece of cake for you

have fun with your experiments!
 
Thanks J! Though my interest in photography is deep, but not at this point in the realm of coating due to other commitments, I'm just wondering why we've folks like me crying for the loss of APX 25 and Efke 25, but no one is making an artistian home brew for folks like me who'd buy a roll or two of 35mm/120 to play around with to 1) support home made goods, 2) a gap in our market? But maybe my query is self answered, Efke 25/APX 25 went under bc no one bought enough....
 

hey andy

i have lack of time too ... so i get my emulsions bottled. it is what happened with me in college .. It was fun to know i could make it in a pinch, but in the end grabbing a bottle ended up being easier .. i would rather eat plain vanila ice cream instead of fancy-stuff too ... coating is just a matter of melting and usunf a brush to paint it on and letting it drt (.paper at least glass is a bit more involved ) ... its not as hardcore as one might think.

have fun!
john
 
Andy;

The market is too small to make some of these items commercially and some of the items you want are at the edge of what people can or will make at home.

So, you can make an Azo type paper in 3 grades and a Kodabromide paper in 2 grades. You can make an ISO 1 - 40 emulsion that is blue or ortho sensitized. Beyond that, things start to get difficult and expensive. They can also get to be very time consuming.

So, we, the teachers and writers of this stuff try to formulate things that are very useful but take a minimum of effort and expense. Of course, it sometimes takes thousands of dollars of R&D to make these work. Most writers freely admit that they have not make the emulsions that they publish. They just copied it from somewhere. And, almost all of those in books are wrong due to omission or comission. Grant Haist published a formula in V2 of his book set and told me that it was heavily edited by the Kodak editors.

PE
 

andy

while much of what PE said is true, if you go to thelightfarm you will see emulsions that people (WROTE AND ) MADE and USED ( including the OP ).
the emulsion i made 25 + years ago was made from a photographic book published for people who wanted to make and use
emulsions ... i dont' remember which one it was, but it was easy ( just a few ingredients ) the publishers didn't make up-stuff and it worked fine ... i haven't made the ones that are in the back of silver gelatin ( the liquid emulsion book )
and i haven't made the ones at the light farm, but the aj-12 emulsion published in the (apug's ) articles section is one that a lot of people have made and used.
its not all smoke an mirrors as some would suggest ...

i must admit it would be very nice to take a workshop with today's master-chefs ... it would be easy to see what it is supposed to be like instead
of a blind guess ..

have fun!
john
 
John, I have read formulas by Baker, Wall, Eder and others as well as copies of formulas from the FIAT and BIOS reports posted here. They all have omissions or errors. True, you can make a functional emulsion from them, but this emulsion is not what they made.

One simple reason is that we cannot buy the gelatin that they did. Another is that they don't usually publish addition times. And if you think that is unimportant, see the graph I posted earlier.

A simple published formula such as AJ-12, published here on APUG cannot be tinkered with unless you know a lot about what you are doing or have some expect backup. This is a Kodak formula, but one that can only be made exactly as written.

PE
 
I plan to take a workshop on emulsion making in the near future at GEH.

We are lucky to have this wonderful group in Rochester and I for one plan to take groups there to our benifit.
 

Oy! Ron,

Yuh just gotta stop saying stuff like this. People take you seriously and at your word, but they shouldn't. I just can't figure out why you want to make things seem so hard. But, words are only words. For more than words, please go to www.thelightfarm.com . The current homepage image (the big one) is AJ-12, coated as film. I made the recipe in a couple of hours, and I wouldn't have even needed electricity if I'd so chosen. Also, less than $5 for the whole batch of emulsion. The modifications I made were only arithmetic and a little trial and error. If you want to call that experience and expert backup, I guess it would be rude to object. In any case, there is a lot of info on TLF and I'm always only an email away. editor@thelightfarm.com.

For even more info, please start here: http://www.thelightfarm.com/cgi-bin/htmltutgen.py?content=05Mar2013.

I am pulling together the next set of web workshops, so stay tuned. Plans are to get through to ASA 100 (summer speed) ortho ("X2Ag") by the end of summer. If anyone doesn't want to wait for more tutorials, there are a lot of proven recipes on The Light Farm.

John: thanks for the support! Much appreciated.
d
 
Ian,

Artcraft has silver nitrate for $379 a pound right now. (I advocate buying bulk, once you know you're addicted to emulsion making!) That comes to a little over $4 for the 5 g used in AJ-12, and the KBr, KI, and gelatin are about a buck total, if that.
 
Hmm, that's tempting. D, uour AJ-12 image looks very nice.

I'm in the process of starting up again.

-- jason
 
Denise;

Yes you can make AJ12 as is for what you specify, or close to it. But I wonder how much it would cost if you began to make those modification you talk about. And then average the cost overall to get the average cost per emulsion. Dont forget utilities! And, how variable are your batches?

AJ12 happens to be very sensitive to fog and temperature. So, it takes some finesse to work with it outside of the formula given.

You oversimplify. I have the experience of dozens of students who worked with me personally in a lab and classroom either alone or along with Mark Osterman and our interns, and I have literally thousands of e-mails from those students and other APUG members. I guide them all by return mail in their trials to alter this or that formula that was either taught to them, read in my book or read on-line. And I have many many personal years of lab experience.

I recommend your web site to my students with a caveat to be conservative in their interpretation of results. Indeed, you are a marvelous photographer, and you did it over years of work. Please don't think of yourself as an instant expert in emulsion making.

PE
 
my apologies to mark for seeming to derail his thread ...
id love to attend more than one of these teachings, but
unfortunately commitments keep me close to home ...

===

hi ron

at the risk of being argumentative ...

i think it is wonderful that you teach these classes with and without mark o at GEH
and i think it is valuable that you have feedback and experiences of "thousands of emails"
but making emulsion does not need to be that sophisticated.
it can be done in a small room by a college student who has absolutely NO emulsion making experience
at 2:15 am using a (then)80 year old recipe, no internet, no seminars, no help
.. i wish i still had prints from that emulsion i made it was OK ...
but i have moved maybe 15 times since then and some things got lost.
one does not need sophistication, one just the will to make it ...
im not saying, it wouldn't be great to have thousands of letters of feedback about everything from
making emulsion, to coating cyanotypes, to making exposures to making prints
but it doesn't need to be like that ...

this whole emulsion thing reminds me of the "mystique" around using large format camera.
people for years told me it is sooo hard, its complicated, and isn't for the faint at heart ..
i bought one and find it to be easier to use than a 35mm point and shoot.


MOST EXCELLENT!

my pleasure denise !
john
 
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kb3lms said:
Hmm, that's tempting. D, uour AJ-12 image looks very nice.

I'm in the process of starting up again.

-- jason
Click to expand...

Great to hear! I'll keep my fingers crossed you find the time.

And speaking of finding time, the clouds here have cleared and I'm heading out for the rest of the day with d.i.y. film in a camera (and truth be told, also a digi P&S )
carpe diem,
d
 
Denise, your AJ12 image is indeed very beautiful. As I said before, you are a very good photographer.

John, you are correct. Emulsions can be made very simply in a small darkroom with little equipment. Mine is 7 x 14 ft.

HOWEVER, you have to be using a cookbook emulsion, and you will not have complete instructions, and your results will differ substantially from that in the textbook. It will look good but have bad latitude, bad LIK, bad reciprocity, bad keeping and so on.. It will probably be blue sensitive and have a lot of halation depending on the image.

If you make 10 or so plates over one hour, the first plate may be ok but the last plate may be foggy and have a different speed. If you make it more than one time it may vary by one stop.

I am trying to FIX some of those problems and to warn those who might try this that they may see it but that it is NOT THEIR FAULT and IT CAN BE FIXED!!!

I hope someone out there is listening and understanding what I am trying to say.

PE
 
Photo Engineer said:
I'm sure it is a wonderful product Andy, but how is it a game changer?

The Photographers Formulary has been selling photograde gelatin for years. Their current products are both from Kodak's former plant in Peabody MA.

PE
Click to expand...

Hi - Sorry i misunderstood your comment, I thought you said something about photo grade gelatin not being attainable but then thought I saw Mirko of ADOX recently talking about this new product.

I appreciate all's comments here, nice to know there are options. Just still wonder why we've no APUG'r selling "Joe's 25 ASA" or "Sally's 25"....guess maybe all that training you all at EH have of Holmburgers might make my dream come true....


I've a bottle of Liquid Light I need to mess with....gotta start somewhere....
 
Andy, one of the points being missed here is that photograde gelatins of the 1920s and earlier were active gelatins and came in 3 or 4 grades which controlled speed and contrast - and caused emulsions to vary a lot depending on the diet of the cows.

Modern gelatins are specially purified to give constant speed and contrast, but this speed and contrast are quite different than the one the 12920s writer intended. Generally, modern gelatins make emulsions that are up to 5 stops slower than those of the 20s and have much lower contrast. And so, AJ12 is nominally a nice long scale emulsion with an ISO of 25 or so if made with old gelatins (or made using modern methods which I teach). Without active gelatins or without modern methods, you get an ISO 1 emulsion with short latitude.

PE
 
I attended a emulsion workshop at GEH a few winters ago - it was wonderful experience.

Ron Mowrey (PE) and Mark Osterman took turns describing the history and process of silver-gelatin emulsions, and guided the attendees through the hands-on portions. It really was "plug 'n play" : Put on a labcoat, gloves and goggles, walk into the lab, and everything was ready: chemicals, glassware, hotplate/stirrer, coating rods, coating wells, paper, etc., Our freshly coated papers were hung to dry in a large room next to the lab. Stacey Vandenburgh (GEH) was invaluable in keeping everything organized and on-schedule. (As if by magic, refreshments such as coffee, tea, pastries and fruit appeared on a regular schedule). We made contact prints on our treasured paper the next day. The group was also lucky enough to view some selections from the GEH archives.

A fantastic experience!

Things were a little different when I got home: small cramped darkroom, a meagre stock of chemicals, no hotplate/stirrer, no coating blades or rods, etc., One can make a basic emulsion with a few glass jars, some silver and salts. You can simply brush it onto paper, and do a few bubbles or dust marks really matter?

So the moral of the story is: yes, a simple, pleasing emulsion can be made easily with a few basic tools. If you want to make a camera-speed, panchromatic film, with good LIK, latitude, and anti-halation, it becomes rather tricky and finicky. You want streak, dust and bubble free coatings? It gets a little more complicated. Now, let's try to do the whole thing again, with the exact same results. Ohoh, perhaps the temperature is one degree off, or it cooked for a minute longer...accuracy and control start becoming significant players. Perhaps one can claim that batch of emulsion costs only a few bucks, IF you don't include the labware, tests and trials, coating tools, hepa air filtration, scrupulous cleaning, precision weigh scales, pH meter etc., etc.,

I sometimes feel that I am cursed with the insatiable thirst to know "why and how" things happen in the emulsion kettle. Good 'old AJ-12 has undergone numerous tweaks in my 'lab': varied addition times, stepped additions, sulfur, TAI-restrained sulfer, dyes and so on. So far, I've only had a few complete failures - most emulsions have been usable and quite capable of recording an image. What I'm learning is of far greater value than the money (a few $k) into building a lab.

Should there be an opportunity to take a workshop at GEH, I would highly recommend it as a fast-track into emulsion-making with some of the best in the business being guides along the way.

A bazillion thanks to Ron (PE) for putting up with my endless questions, supplying answers and suggested reading, and providing much "hand-holding" along the way.
 
Many thanks Ian. You are one of many that are holding my virtual hand over the internet. Mark is doing the same. Only, next week he is sailing down the Erie canal with Chris and Nick. They are doing dry plate (IIRC) and supplying period music with banjo, mouth organ, washtub and guitar. Knowing my limits, I am staying out of this workshop!

Best wishes to al.

PE
 
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