viewing emulsion under a microscope
Is there a way of using an optical microscope to examine grain size, distribution and shape? Do you have any thoughts on magnification and / or microscope type? How would the emulsion sample be prepared?
I've had developed emulsions under a microscope:
That was with a 10x objective, no eyepiece and a home made camera adapter.
I've also tried looking side-on at emulsions under the microscope. I found it helped to swell the emulsion first, otherwise it's all base and a tiny layer of emulsion on top.
The most difficult bit was cutting the edge accurately enough, as I don't have a microtome.
Lens caps and cable releases can become invisible at will. :D
Bob, without wanting to seem snarky--what is the purpose for doing this? I mean, I'm no stranger to purposeless activities myself ( ) but what does this achieve?
Best holiday wishes.
Hello Mike, Ben....
A long time ago, I remember seeing an article where the writer made a microtome from a 3/8 - 1/2 inch (10 - 12 mm thereabouts) diameter nut and bolt. He rotated the nut to almost the end of the bolt (before it would normally fall off) and embedded the object in epoxy (or wax, I think) in the open space. Once the material hardened, he rotated the nut onto the bolt in very small increments to expose the embedded material, and sliced off what he needed. I will have to draw a diagram and scan it in later on.
This is a good question, and I don't mind at all.....
The reason I am asking about the microscope is that I believe it would be helpful if you could actually see what kind of grains (size, shape, etc) result from the different emulsion types and formulas that are possible - when you make them in your location. Even if the formulas are followed exactly, there are different factors in play that can change things. Do you have hard or soft water? Other elements in the water? Copper pipes or PVC or cast iron? Is your thermometer / thermostat / heating element calibrated? What are you using for a timer? Addition rates and methods over time? Things like that. I would imagine that it would be very revealing if you could actually see what kind of grains result from a particular emulsion making setup and procedure.
Thanks, and have a great holiday!
Last edited by rmazzullo; 12-25-2008 at 09:34 AM. Click to view previous post history.
Reason: corrected info
Well, duh, it makes perfect sense for an emulsion MAKER. I'm just an emulsion-exposer, so what would I know?
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I could see where it might be interesting to see what you come up with after the emulsion is exposed and processed. I guess it depends on how far you want to take it.
Originally Posted by MikeSeb
Sorry to be in a snarky mode, but it's 1PM and the adults haven't opened their presents yet.
The purpose is to have an excuse to buy a [better] microscope
Best holiday wishes to all, and a Merry Christmas to those who need one.
A microscope at about 2500X or higher with oil immersion if possible, will help one view layer composition and developed silver grains as well as dye droplets in color film. This will show gross structure for comparisons. We use this primarily for film design analysis. It is rather coarse and low resolution for anything other than this type of work.
For details and emulsion work, you have to use an electron microscope to see grains and you need something on the order of 0.1 - 10 micron scale to do this. The grain must be made into a carbon replica or the like and the gelatin must be removed to prevent obstruction of the image. These have to be done in specialized labs and are pretty pricey. The silver halide grains are outside of the range of a microscope except as featureless dark dots in most microscopic pictures.
Mastering the microtome method for film analysis is a painstaking job for a craftsman. The microtomed section must be mounted flat in order to see the object correctly. I worked on this for hours at a time, but was never really any good at it myself. We had an open lab for this type of work, but I ended up having to submit my work for a pro to do it.
As a side note, the guy who I usually worked with was a nephew of Anton Dvorak the famous composer. He was a resistance fighter during WWII and had some amazing stories to tell. He was a true artist with a microtome and with the microscope.
PE beat me to the punch.
What you are seeing with an optical microscope is not the grains, but clusters of grain.
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Damn...0 for 2. I'm on a streak!!
Thanks PE and everyone for their input. I guess I'll have to wait until an electron microscope comes up for sale on e-bay. (I'm just kidding).
Happy holidays to all,