The attached pictures show why! I am taking HRSTs advice!
Kodak had patented an addendum that increases speed and contrast of a given emulsion. The pictures below show examples of an AgBr emulsion with 3% Iodide and a Sulfur finish that compare surfactant X and Photo Flo 200 used as surfactant.
The results show that there is an ingredient in Photo Flo that is covered in that patent (well, I knew that ) ! The results are about 1/2 stop in speed and about 1/2 grade of contrast. These two photos were identically exposed and processed.
This does NOT work with several other emulsions that I tried, but it does work with this one on a repeatable basis. There are several other compounds that do the same. I hope to report on them as well.