Hi PE,
Thank you for your great reply to my qestion.
I am not abandoning silver/gelatin emulsions. But someone at APIS sugested trying dry plate collodion.
Going through the literature from 100 or more years in the past,it is obvious that ortho and panchro plates were made by dye adition, not by an increase in iodide. That was probably a misinterpitation by Waldack.
Many of the dyes used to sensitize collodion were also used in early dry pate gelatin emulsions.
I have done only a little work with the Sands dyes because of the cost. But,if all else fails......
Bill