Every work carries an item number, its copy number within the edition and a certificate: series, technique and principal layers, dimensions, year, the studio’s mark and signature. The certificate travels with the work and is duplicated in the studio register — the item number confirms the authenticity and history of the copy.

Each design is limited to an edition of 300. Copies of one design are executed by hand and differ from one another: not copies but authorial repetitions.

The certificate is part of the work: on resale it passes to the new owner, and the register entry is updated on request.