Rosenthal pottery marksRosenthal pottery marks. . Why the marks are important. Art pottery departments were established in 1910 and in 1920. : Frequently Asked Questions. This is one of many marks used by Rosenthal on various lines. Identify Porcelain marks, Pottery marks, China marks quickly & easily ONLINE! . . . . Marks and Backstamps on Porcelain and PotteryFrom About. Ceramic marks are applied in four basic ways: incised, impressed, painted, printed(Rosenthal | Pottery & Porcelain... more