Restoration of an 18th century frame: 3D modelling, printing and matching color of decorative flowers elements

This paper describes the application of 3D digital technology to support the rebuild of lost decorative elements of an historical frame. The frame belongs to an 18th century painting depicting the portrait of D. José, Prince of Brazil, displayed at the National Palace of Queluz, Portugal. The application of digital technologies has been planned from the very beginning in order to avoid the traditional use of silicone in the reproduction of missing elements. The photogrammetric 3D acquisition, a non-contact methodology, has been used to reduce the manipulation and hence prevent further degradation of the artistic object. Following the 3D modelling operation, new decorative elements were made using an additive printing technology. In the final phase of the work, the post-printing treatment was carried out, in which aqueous products were used. 3D modelling, in addition to facilitate the restoration treatment of the historic frame, can also be useful in the creation of a digital collection of decorative frame elements, i.e. a virtual database.