For the last several months I have been working on the calculations and preparation for making a new, high speed emulsion.

Basically, it is a high iodide, coarse grained emulsion that uses vAg control or detecting to get to the "right place".

It required about 2 hours prep, and about 3 hours run time, but this did not include the months of calculations and attempts to buy tubing and set up the vAg control. There are several posts on both of these here on APUG.

In any event, I finally go the #13 tubing that allowed me to make a 1 Liter run which used nearly 1/2 pound of silver or about 250 grams. Wow! Anyhow, over the 3 hour run, I was off by 1' 30" which is not bad. It took me that extra time to get to the vAg calculated so I felt pretty good. One liter is the minimum that can be made with all peristaltic pumps that I have found on the market. Changing flow rate will not give the right results.

Now for the problems.

1. It was very foggy due to the high speed and probably small light leaks over the 3 hours. (or me )

2. There was a lot of aggregate formed, probably due to poor mixing and the very low pump rates needed for such a small batch. This is inevitable. I will need to achieve probably 4000 RPM with a strong mixer as I could only get to 700 RPM with a magnetic mixer. In addition, I may need baffles in the beaker to break up the eddy currents and etc. to allow better mixing.

This is beginning to convince me that making modern emulsions is going to price itself out of the range of most makers due to the requirements.

I have also found that the automated equipment that might be desirable is quite pricey as is the very simple tubing and the tubing is very hard to get.

So, I have what may turn out to be an ISO 400 emulsion but may take me weeks to get there requiring calculations to figure out the sensitization needed for this emulsion and the amount of antifoggant to prevent total fog formation.

I will try to update this as I can. This will probably be in "the book" which is in version #5 and the changes have all come from suggestions after reads by associates and friends.

My thanks to them.

I would like to add my thanks to my wife for her patience with me. She broke her leg last year and spent a year recovering with 6 months in a wheel chair. This kinda slowed me down. This is my first public comment on this, and I mention it to help explain some of the delays. Sometimes, the best laid plans .... etc. Anyhow, my apologies for being so tardy.

PE