German Porcelain Coins - Gipsform

Gipsform = a plaster mold, lit. "gypsum mold." I have seen the term myself but I do not have a lot of these, just a few Meissen in the red Boettgerstein, so this is far from an area of great familiarity to me.

DE wiki has the following in regards to the Böttgerstein Porzellangeld:

"Die seit der Mitte des 19. Jahrhunderts gebräuchliche Reduziermaschine, die den Entwurf mechanisch in das gewünschte Format verkleinerte, lehnte Börner ab. Er schnitt seine Entwürfe in der anspruchsvollen Technik des Negativschnittes direkt in die Gipsform."

Translated, Börner decided against using a reduction lathe, which was common by the 1900s to create molds from master casts, in favor of the technique of directly cutting the negative impression into the gypsum mold (Gipsform).

Possibly, the white porcelain was used to prove the molds, and make high relief trial pieces, but then it was switched to firing the red Böttgerstein for durability, impermeability, and resistance to discoloration in use. From looking around, the white porcelain issues seem to be very scarce to rare for the Notgeldmünzen, but more common for the medallic issues.