Bill, I might be on my own here, but I don't think zone stickers, grey scales, power dials (whatever that is), BTZS etc really improve or add value to the Zone System from a printing perspective.
The Zone System (Adams/Archer) is an introduction to visualization, spot metering and sensitometry with the goal of eliminating some of the guesswork involved in making negatives that contain the information required to make a print that carries the desired effect. Print controls are then they key to extracting the information from the negative, which is why they should be considered when making the exposure in the field. A careful reading of Adams and this becomes clear. You can't make great prints by trying to make negatives that print themselves.
Considering the Zone System is an introduction to the system of controls and sensitometric transitions from subject to print, to me the logical extension of it is tone reproduction theory. If one truly wants to be able to "place" subject luminances on expected print tones (and we can debate the utility of that), I believe a study of Jones, tone reproduction diagrams etc. is the way to go. That is how to extend the Zone System. Of course, that inevitably involves gaining a better understanding of exposure as well (film speed for example).
Just to set the record straight: I do use the Zone System, just do the calibration without a densitometer (á la Minor White, Zakia, et al.). I think that applying sensitometry in an uncomplicated way helps make the system what it is, but its greatest advantage for me is as a visualizations tool. Extending that tool to include print controls seems only logical to me. Michael says it very well below.
I agree with you. It is a simplification and I generally like the Zone System (Adams/Archer, not the variations by other people). But I think many people who read about the Zone System misinterpret it as a way of directly controlling all the print values with negative exposure and processing. Very broadly, perhaps. But not really. If that is the way someone wants to work, he really needs a better understanding of the transitions from subject to print, the variables, controls and limitations.
I also agree with your last statement, which was more or less the point I was getting at. The more rigourously you "extend" the Zone System by applying exposure theory and tone reproduction theory, the less use you have for the simplification model.
I spent most of today at GEH helping two interns learn how to conceive and design a new emulsion. This has resulted in many fine plates, and many fine prints. We didn't mention the zone system one time. We didn't even mention H&D curves. That will be for the near future though.
Then let us, as I proposed earlier, for us to teach a joint course in this subject, ie, the design of photo neg-pos materials!
Every time I hear about what you are doing at GEH, I think how trivial it is to talk about using emulsions, as you are creating emulsions...
No, don't talk Zone System at those workshops - that would be a waste of time.
Talk about Zone System during downtime.