A-Z of Ceramics - Z is for Factory Z
Factory X, Y and Z were classifications given to three groups of late 18th-century English porcelains formerly attributed to the New Hall factory in Staffordshire. Following detailed comparative analysis of their potting and decoration, collectors established that they were made at other, as then unidentified works, even though they were dependent on New Hall's innovations in technique and derived in part from New Hall's patterns and shapes.
Further unattributable groups of this type have been discovered since the original trio were first identified in print in 1971. Indeed, one authority has suggested that collectors and connoisseurs could just as well have started at 'A' and worked through the alphabet in attempting classification of these problematic wares. Since then Factory X has been identified as the Tunstall works of A. & E. Keeling, but Factory Z is still a puzzle.