Thanks for your confidence in Glen and I.
I know that Glen has deep reservations that any of these designs originate other than with Douglas Jenkins. I have found no contemporary support for the idea, that any "Barolac" designs were executed by Rudolf SchrÃ¶tter, despite several items being attributed as such in the 1972 Gottwaldov catalogue.
Certainly, for the most part these are 1930's designs, (the pattern number clearly falling within the 1930's,) and with the exception of the Barolac "Marguerite" pattern, (for which there are well documented additions to the range) and Glassexport marketing issues in the 1960's, for the most part, these remain undiluted by later additions to the ranges.
Opalescent does seem to be an inter-war characteristic, as little opalescent appears to have been made post-war, and what post-war production there was, for the most part, seems to be of inferior mould quality.