Denise, I have examined literally thousands of emulsions over my 15 years in Emulsion Research. Of those, very few used any form of Ammonia, and few used Digestion. You see, if you want a cube (Essential component of Ektar 100) you cannot digest as it rounds the corners and you no longer have cubes.

If you want a thin t-grain, use of an Ammonia digestion will change thickness or shape. In other words, very often Ammonia keeps you from getting from here to there. Ripening works (no solvent) but digestion is an impediment.

So, out of these thousands of emulsions, very few used Ammonia in any form. Then too, we had more recent methods of doing a digestion, which is far far beyond the scope of the work we might discuss here.

And so, as an easy way to make a fast, single run emulsion that is fairly monodispersed, I used the Ammonia digest that is in my book and posted (in part) here on APUG. It is subject to fog but has reached speeds of ISO 40 - 80, and I have made an ortho version of it.

We do not plan to do that at GEH, as the Ammonia fumes, even in trace amounts, can be detrimental to the rare objects preserved there. We are approaching the speed angle from a different POV.

As you will find, Ammonia digests of any sort without massive ventilation is quite daunting. However, my current and past comments are not mutually exclusive but merely reflect a broad range of possible emulsion types.

We had over 200 emulsion makers in our division (and WW). They averaged 1 emulsion per week. This is about 1000 / year and over 15 years is over 10,000. They all did not go into production, but just about every one passed through my hands or the hands of a member of my group at one time or another. I cannot generalize these easily, but can say that the use of any form of Ammonia was a rarity.

PE