Well today I decided to learn more about the thickness control of the Fuji instant products which have a thinner emulsion and better sharpness than some of the Polaroid materials such as 669. What I found is interesting: Fuji is using their well controlled film base of what appears to be PET. Careful measurements show very consistent thickness. Also the masking layers are very dense, consistent, and have very high opacity. These are not easily dissolved in water but require bleach to separate from the film base, which has been reported by others.
I am collecting all this data. A very useful tool has been the gage block comparator, which measures to millionths of an inch. (or meters if you must)
There is a lot to do to establish new design schemes using traditional film emulsions as part of silver migration systems. Our work in thin films (look up "roswellite" in google for instance) and coatings used in medical devices leads me to think that there may be a new strategy for producing an instant, very high quality negative at 4x5 and 8X10.
If you have just become aware of this project, and wish to help, you are most welcome. This is not intended to lead to any large industrial or commercial enterprise - far from it - it is intended to promote art, and if it can do that, at reasonable cost, we will all have more options to express visual ideas in the future. I am looking for people who worked at Polaroid or Kodak with deposition experience, a chemist familiar with silver migration kinetics, and other interested tech types with ideas of how to pull this off. I have many. If you are in the Boston area, so much the better. Please make yourself known! Perhaps we can catch up at PHSNE, or somewhere else.