Well, to clarify something I posted earlier, A&T do describe the extra ingredient(s) in Microdol X, as described in the patent by Henn. I wanted to dispel that mystery.
Originally Posted by Ian Grant
Now, on to HDD developers. As I have explained before, electron pump or electron transfer agents were at the top of the list for investigation. I have already implemented that in Liquidol for papers. They give long lived developers with good activity and high capacity. For films, they can give High Definition by alteration of the basic formulas.
Iodide was seen to be an inhibitor of edge effects kind of like a buffer against them taking place. With higher iodide levels this became more apparent, and therefore HDDs with iodide were viewed as being somewhat passe.
In fact, on the triad of Sharpness, Speed and Grain, it was found that at best you could strike a happy medium getting 2 out of 3, but getting a slight optimum of #3 by the right formula and this is what an HDD tries to do. It gets Sharpness at its best and then gets the best of the other 2. This is achieved by moderation in the activity of ingredients that control the other two. For example, Sulfite controls grain, is a simple statement but can serve as an example. At high concentration, you lose sharpness but improve grain.
I believe that Kodak has this triad mapped out in a graph on their web site along with developers placed on the chart to show how they affect these three characteristics of film. If you look at the chart, and compare with formulations, you will see what I mean in the above.
In the final analysis though, there is no magic bullet and we cannot go backwards in time and expect improved results, especially with modern films. This was the bottom line with our R&D.