Re: looking for people who make photographic emulsion

From: Jeremy Menzies (email suppressed)
Date: Mon Mar 01 2010 - 11:50:10 PST

Hello Frameworkers,
Sorry for the length but I thought being thorough was better than not...
I've made a black and white emulsion from the raw (and somewhat basic) chemicals with a pretty good degree of success. The emulsion I made was very slow but I've come across information online about how to boost speed through 'ripening'. Unfortunatley, I think it's very difficult to home-make an emulsion with an ASA close to the manufactured kind due to chemical, equipment, and recipie limitations. BUT, you can boost the speed and technically, any speed is 'shootable', in a single-frame situation (although I'm sure you are thinking of shooting at a somewhat normal camera speed).
So, my emulsion consisted of Unflavored Gelatin (the purer the better), Distilled Water, Silver Nitrate (AgNO4), and Potassium Bromide (KBr), both chemicals are available from Photographer's Formulary at decent prices. They sell bulk amounts of both or custom measured amounts, for those who do not have the equipment to measure out from a bulk container (or who only need a bit). It think I bought the 10 gram size of AgNO4 and a custom measure of KBr to make it easy. Gelatin can be bought at any decent grocery store and really pure stuff can be found online (I got mine at the grocery)
I used a recipe I found on a site which I cannot find anymore, but it looks extremely close to this one HERE (and pasted below). As you can see, the basic process is very simple but does require being very very careful and exact. Silver Nitrate and Potassium Bromide are very hazardous (Silver Nitrate more so) so protective gear and a constant safety vigil is essential. Be sure to download, print, read, and understand the MSDS sheets for both so that you know what to expect and how to handle any emergency. You can also request copies of these from Photo Formulary with your order.
Now for a bit of the fun part. Making the actual emulsion was surprisingly easy and I was able to get somewhat consistent results by being incredibly meticulous and making notes on everything that I did. One has to think of it as a pretty serious science project in order to figure out how to understand and repeat effects. I'll briefly sum up what I did and what happened.
I made an emulsion, coated 35mm clear film strips with it, exposed photograms of object onto the strips using a photo enlarger, and developed them in photo paper trays. Then, I took the strips (now negatives of the objects exposed on them) and re-photographed them onto 16mm print film (the standard HiCon from Kodak available in 400' rolls) using an optical printer and moving the strips around in a homemade gate (from an empty 35mm slide holder) to create motion, rhythm, etc. Then, I processed the 16mm as a negative to reveal a positive image of the original photogramed objects. Then, I played around once I got some results and tried different things for different effects. It got more interesting every day (I worked on it for about 4-5 months)!
More Details:1. Make emulsion.2. Coat a substrate.I used cleared 35mm ligth struck leader as my primary substrate because a.) it's got a larger surface area than 16mm or 8mm and b.) light struck leader that is cleared using a hypoclearing bath still has a factory-coated gelatin layer that I think helps the homemade emulsion stick better. One couls use a number of different substrates and could easily coat 16mm for use inside a camera.
3. Dry coated items.This must be done in TOTAL darkness, I found it easy to do with the 9-11inch strips of film inside a photo paper box. If you've got a darkroom where you can hang the film to dry at least overnight, sometimes longer (shorter w/good ventilation) then I could easily see coating a lot of 16 and hanging it in long strips.
4. Expose coated items.I used a photo enlarger and photograms, one could just as well roll up some 16mm onto a daylght spool and pop it into a camera. A note on camera exposure: a.) the emulsion is pretty fragile and not so even, I found that there were little crystalline structures that formed on the surface of the film during the drying that could scratch or cause the emulsion to flake off. It's somewhat hardy but I don't see it running through a camera at 24fps without having at least a tiny bit of damage (but with a project like this, you've got to be a little open ended and you probably wouldn't get any image at 24 anyway). b.) don't plan on using your best 5000$ camera for this, the emulsion might scratch the gate or flake off into the shutter or who knows what, so I'd say just be aware of the possibility of camera dirtying or maybe damage (I doubt that it'd damage it, but one never knows...)
5. Develop.At this point, it's harder to find a good lab to do almost any film work, so finding a lad that'll handle your homemade, super fragile emulsion is incredibly unlikely. Plus, if you make your own emulsion, you can probably manage developing it, too... I encountered a few things with mine when developing that made it more interesting and somewhat difficult. One is that the emulsion is EXTREMELY fragile when wet and immersed in chemistry. Using open photo trays under a red safelight (my emulsion was slow enough to use a low watt safelight), I was able to monitor the surface or the film and somewhat control the emulsion from sliding off completely, although I did have that happen. It can look INCREDIBLE if you catch it and get it to stick, but it's also easily lost, which can be a little frustrating. Developing 16mm in a closed tank might be a little tougher and you might wind up with a sludge of exposed image at the bottom of the tank when you open it up. Unless of course you can devise a better way to make it stick...
I used Kodak's D-19 to develop both my original film strips and my print (I think, maybe Kodak's D-76 for the originals, I'd have to check my notes), with good success. You can try other developers, I suggest ones that are made more for hi contrast developing, as the homemade emulsion is a little on the silver (grey) side but, try different ones, maybe Dektol (Kodak, used for photo paper) or some others.
A note on developing and fixing- my emulsion was thicker in some places and thinner in others, so i wasn't always able to get the same even results across the lot of it all. Also, I leaned more towards the longer time side in fixing because I was afraid I'd lose image from under fixing. Some spots remained undeveloped and showed up as dark spots in the 16mm film. I haven't looked at my originals in a while, so I'm not sure how they've survived the past few years (I hope they're not brown!)
6. Dry. Can be in light, now that it's all developed and fixed.
7. Look!This is the most exciting part. When I was able to watch the objects burned onto the 35mm film strips move around on a screen from my 16 print, I was absolutely elated. Watching is also a bit of the science end too because you can match your exposure and developing notes to what is actually seen and thus try to reproduce effects.
This kind of project is a lot about patience and diligence, recording every little thing, keeping a lot of constants, changing only ONE variable at a time, and being very open to repeat failures and changes in the plan. Which, I found made looking at the final product all the more exciting and satisfying but can also be super frustrating after hours of work in the dark with no results.
On boosting emulsion 'speed': I came across another recipe that was similar to the one I used but involved re-'ripening' the emulsion multiple times after the initial mixing and hardening. Since it's suspended in gelatin, you have to reheat the emulsion every time you need to coat something. This process involves reheating, straining through cheesecloth, cooling, and repeating this to boost sensitivity. HERE's a site that I just came across, that although different from what I found before, it's a similar process. This recipe calls for Potassium Iodide as well as the Potassium Bromide.
There's a lot of information out online with formulas and pointers on what to do and how to do it. I'd suggest looking into some of the alternative still photography forums where people are talking about their experimentations. Also, I'm willing to provide any additional information about what I did and how I did it.
FYI, here's a little picture from the film I made (please don't copy it):
It's not the greatest image but gives a little sample, I hope.
Hope this helps,

> Date: Sun, 28 Feb 2010 23:06:07 -0500
> From: email suppressed
> Subject: Re: looking for people who make photographic emulsion
> To: email suppressed
> a grad student here is working very hard on an albumen emulsion. Still experimenting but getting lovely results. More news as it develops ;)
> __________________________________________________________________
> For info on FrameWorks, contact Pip Chodorov at <email suppressed>.
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For info on FrameWorks, contact Pip Chodorov at <email suppressed>.