I have an OT question though, is that Little Mountain in the second photo?
No. It is called Blue Mountain. There are several hills about the same size around here (San Bernardino County, CA). They are not very high. But Mount Baldy is a real mountain, about 15 miles away.
Some questions and thoughts after the fact.
What is the iodide content?
How do you wash out excess salts? If you do not, how do you prevent crystals from forming and the surface from being tacky from the salts and surfactants (if any)?
Ken - thanks for finding that photo. I had that same feeling as you.
Originally Posted by Ken Nadvornick
Ken and Kirk,
Actualy, in "real life" the two look almost identical as far as grain and color are concerned. I don`t know why #1 looks so grainy and yellow in the scan.
I "pooped-out" last night. But I will coat more plates today and scan several.
The moler ratio ratio of Ag:Br:I = 1:1.02:0.02.
One of my goals was to make an emulsion which dose not require washing. I
minimized exess Br in order to do this. Also, I forgot to mention, the emulsion contains no ammonia.
The emulsion does contain 1 molar equivalent of Nitrate per unit volume though, which can crystallize out and also cause tackiness. This is one of the reasons I asked.
This may be why the emulsion is prone to bubble upon drying, if the wet film thickness is too thick. Partcles can create bubbles. Prior to very recently, I relied on the tape thickness on the ends of my puddle pusher to controle wet film thickness. Then I purchased a wet film gauge. I found that my wet film thickness was actualy 12-14 mils, not the 7-8 mils that I had presumed. Reducing film thickness to 7-8 mils got rid of the bubbles, so far.
I will make the higher speed emulsion today, coat this afternoon and have more plates to show you tomorrow.
After looking through my old emulsion work, I find one interesting thing. Most polymers useful for "peptizing" or making an emulsion were not best for coating it. You had to mix two polymers. One was used for making and a second polymer was added for coating. I have several Defensive Publications and Research Disclosures on this. The rest is confidential.
We also attached couplers to polymers to make color coatings.
I cannot help you with the RDs and DPs, as they cost $$ to read and copy.
In any case, useful perhaps to you.
I recall PE saying something about how the quality of gelatin that's available doesn't allow for fast film speeds. A few weeks ago I remember remembering this and thinking, "well then, why not use something other than gelatin?" Good to know that someone with the ability and knowledge to use that idea thought of it first. Fantastic stuff.
You mentioned that this emulsion was coated on glass plates. Is it possible to coat the same stuff onto a film base or instead?
As stated above non-gelatine binders have been used before. Even after the period of collodion there had been attempts in the last century and one system with synthetic binder was even commercialized but was not successful.
What is your main intention behind going the non-gelatine way?
Perhaps I am too skeptical, but I am un-convinced.
I don't like being unpopular, but despite risking being hated by everyone, I feel the rxn here has been way too positive!
There has been a lot of work on gelatin substitutes... I have several entire volumes on the research right here, and many of them attained or claimed to attain some degree of success. The problem is how they compare to the best gelatin emulsions... at the same grain size... ease of manufacture, and their usefulness with different treatments that one may wish to subject them to..
Non-gelatin emulsions are not new. As AgX mentoned, they have even seen commercial daylight, but at least in the case I heard about, it was later discontinued due to problems that eventually surfaced.
However, I do not want to discourage you! On the contrary, I, being a vegetarian, am very interested in success in this area. The real question is how does it compare to the best gelatin emulsions that can be made.
The fact that you have entered a CA limits the usefulness of any thing you do, unless you are wildly successful... and even then, without the details of the process, I doubt I would benefit from your process.
(Yes-I know you are not doing this for my benefit. But we must look at this in the larger scheme of things... for whom is your effort going and what lasting benefit will it provide to the field?)
Again, sorry for being the sour lemon in your water glass; I hope we can still be friends.