Ron, Is not mixing emulsions on a bench, like some of us are doing, "arcane"?
I thought that keeping alive these "arcane" practices is the whole point of your Wokshops,The Light Farm. and this very Forum. If not, lets all just purchace digital camers, the latest Photoshop and "To Hell with It"!
Just for the record: I for one have never said that I had any knowledge of Emulsion making, other than what I learned from you and a few others. All I said is that I was "practiced" and "Pracice" includes a bunch of failed attempts.
Joy anf Cheerio to All,


I forgot to reply to this.

I am trying to make emulsion making as fool proof and "un-arcane" as possible in my formulas. I hope you saw that in the emulsions we made. They are just about dump and stir.

I'm trying to make the advanced emulsions easy as well, but they will cost more in terms of equipment though.

I have not addressed finishing yet, I've merely used a standard condition more or less worked out by trial and error here at home with the bench top emulsions.

I was not pointing a finger at anyone here in this thread, nor intending anything bad about anyones work. Sometimes though I feel like a person who has started a huge rock rolling downhill. I have to step back to get out of the way. Other times, people point at me and say "its all his fault and he doesn't know what he is doing" as the rock goes bounding down hill.

So, that is all there was to my comment. I feel as if I want to be there to help!

Now for finishing, you are using thiocyanate + gold. Here is the order of use timewise from early days to modern:

Active gelatins > Allyl Thiourea > Thiourea > Thiocyanate > Sodium Thiosulfate

Gold was used after about 1945 at Kodak with all of the above, but hypo was used exclusively for Sulfur sensitization since the 50s or 60s. Of course there is Reduction Sensitization (R type) which uses Stannous Chloride and a whole variety of other methods. Hypo seems to be the compound of choice for sulfur + gold though, but the hypo must be freshly mixed.

Hypo and the others above put Silver Sulfide specks on the grain, but Stannous Chloride forms Silver metal specks on the grain.

Other methods include addition of strong alkali, strong acid and a host of other methods to form a speck on the grain to "jump start" latent image formation.