View Full Version : Higher contrast\less fog
09-15-2013, 09:13 PM
In using my latest batch of emulsion, I decided to just keep it in the tall stainless steel developing tank for melting and refrigerating. After a couple of cooling and melting cycles of the whole thing I noticed the image is clearer in the shadows and has more contrast. There must be some additional ripening or digesting going on with reheating several times.
09-15-2013, 09:31 PM
While I wouldn't mind being involved in the emulsion making community, I'm nowhere near able to contribute to your thread - other than to say ... keep up the good work.
09-15-2013, 09:39 PM
Repeated melting/cooling of an emulsion is going to change its sensitivity, contrast and fog, as well as changing (damaging) the gelation properties.
Is this an unwashed or washed emulsion?
09-16-2013, 12:32 PM
That's interesting. I have to agree with Ian that it's not something I would recommend but you seem to have come across something useful.
FWIW, I do keep my emulsion in the digestion kettle (a heavy bottomed drink glass of some sort from dollar store) which is stored in a stainless "emulsion can" (cheapo kitchen canisters) in the refrigerator. FWIW, when I decide to make a few rolls out of a batch, I dig out the amount I need with a tablespoon and melt in a second container in a little potpourri crock pot I found in my mom's garage. You can pick up some cheap stainless spoons (you need metal ones - plastic will break) at your local dollar store so you don't need to steal from the kitchen. The remaining portion goes right back in the fridge.
Never underestimate the value of the local Dollar Store for finding emulsion making gear.
09-16-2013, 03:15 PM
I normaly do put the emulsion in a smaller container and take only what I need, but as an experiment I remelted the same emulsion everal times to see what it will do. It is a washed emulsion.
09-17-2013, 04:45 PM
Each time you re-melt the emulsion, you are likely ripening it a little more. In addition, unless the emulsion is continuously stirred, there is probably some settling of the grains - the top of the beaker has different sized grains than the bottom.
09-17-2013, 04:56 PM
I donít know if this helps, but with regards to liquid emulsion, I decant into a dozen or more 35mm cassette containers and keep them inside a dark plastic paper box print bag, in a tray. In this way I can put one or more in hot water before use, without having heat up the whole batch.
09-18-2013, 10:41 AM
An open question to anyone: Why do you only coat a plate or a few at a time? There must be a good reason, but I'm stumped, except maybe a space issue (??) I'm limited in my darkroom space, so I can only coat a dozen 4x5's at a time, but it's really nice to have that many.
09-18-2013, 11:14 AM
I do'nt coat too many plates at once because if they sit for a long time (month or two) they start to loose density, so I only make what I think I might need for the time beeing.
09-18-2013, 11:25 AM
Space and time constraints usually limit me to coating 12-20 plates at a sitting. For this reason, I only wash the amount of stock emulsion that can be used within 24 hrs, melt what I can coat at one sitting, and keep plates refrigerated if I'm not going to be shooting them within a day or two. I'm in the habit of adding an anti-foggant (TAI) to every batch to lessen any "after ripening" during storage.
Comes the happy day when I can enlarge my lab area, and not have the distraction "regular work", I'll be able to scale-up the process.
09-18-2013, 12:20 PM
Ok, that makes sense. Between the plates I set aside to compare with other recipes and my shooting, I make at least one set of plates or batch of film a week. I don't have much space, but I do have the luxury of time these days.
One comment -- plates shouldn't lose density in storage or need to be refrigerated. I have plates that are two years old that expose the same as fresh plates. They have been stored in a light safe at room conditions (which because of where i live never gets really hot, but the humidity is always high). If anything, a plate will gain density with storage. It is essentially continuing the ripening process, albeit very, very slowly. Unless you are maniacally consistent with all exposure conditions, you'd never even notice the difference, especially if you develop by inspection. If plates lose contrast and sensitivity under reasonable storage conditions, it is likely that the emulsion was originally over-ripened after washing, or an additive to the emulsion is causing fogging. An emulsion really doesn't require much beyond the basic ingredients (in my experience, for what it's worth -- but I've made a LOT of emulsions over the last eight years.)
09-18-2013, 01:40 PM
For me it is just a matter of time to use up what I have coated. I figure it's better off cold in the can than finished and coated but I could be totally wrong, too. For some reason I can't get over the idea of shooting frugally like I'm using Portra. I hate wasting film. But handmade emulsions should be shot up and enjoyed. (Actually the Portra should, too.) Once it's gone you get a new excuse to make more.
09-18-2013, 02:46 PM
I don't think there's any question that emulsion is better off out of the can and ready to shoot. It's a trick, though, to flip the switch from emulsion researcher to emulsion user! I certainly struggle with it.
The way I see it, there are at least a couple of reasons to get into handmade materials. The pure love of history is one. Another is being able to fulfill the basic human drive to get really good at something. The history of photography is all about new materials -- rapidly followed by the old materials disappearing. We can take that particular issue into our own hands (unless you're fixated on Kodachrome or other sophisticated color materials.) Make your own b&w negatives and/or paper, and make your own processing chemistry, and you've got your whole life to create your legacy.
The real selling point with a whole lot of people just might be the price point of d.i.y. At 5 bucks, more or less, for a dozen 4x5 plates, "chemical photography is too expensive" just doesn't hold water.
OK, packing up my pom-poms before I start to annoy people :).