Polychromy in sculpted artefacts

Objectives

MS-based ancient protein sequencing will be used to confidently identify the biological species of origin and the raw materials, such as milk or egg fractions, used as binders in the polychromy decorating ancient sculptures and architecture (marble, alabaster, limestone).

Expected Results

The project will allow to better understand the original appearance of painted objects. This knowledge will be fundamental to plan long-term preservation and restoration and to define optimal conservation and display conditions. The proposed methodology also allows retrieving and quantifying patterns of degradation affecting ancient protein residues, to distinguish original paint traces and later treatments and brush-ups, ideally providing direct evidence to reconstruct the history of conservation for a specific object.

My project

The study of the polychromy of ancient artefacts over the past decades has completely changed our perception of the ancient world and its aesthetics. Ancient art and architecture was very far from the pure white we usually see in museum exhibitions, but rather vibrant with colour and it is now acknowledged that colour was an integral part of shape. The choice of the binding medium was of crucial importance to the final appearance and effect of the polychromy. The perception of a painted object is the final result of how the complex and highly heterogeneous structure of the paint interacts with light.

Understanding the composition of paint binders has paramount relevance in leading to a better understanding and perception of the original appearance of painted objects. In this thematic section of the project, MS-based ancient protein sequencing will be used to confidently identify the biological species of origin and the raw materials used as binders in the polychromy decorating ancient sculptures and architecture. This knowledge will be fundamental to plan long-term conservation and restoration, to define optimal conservation and display conditions, as well as to prevent or reduce decay processes.

Proteomic analysis will be applied to a number of selected paint samples from architectural elements and sculpted artefacts in the collection of the Ny Carlsberg Glyptotek (NCG). Focus will primarily be on artefacts in stone (marble, alabaster, limestone), and unfired materials. The proposed methodology also allows retrieving and quantifying patterns of degradation affecting ancient protein residues, to distinguish original paint traces and later treatments and brush-ups, ideally providing direct evidence to reconstruct the history of conservation for a specific object. Ultimately, this will provide a crucial contribution to the study of ancient art and architecture, since it will provide vital information on the appearance of the original colours and the techniques employed to obtain them.

Networking

Planned secondments:

  1. Secondment period of 4 months in USTL (co-supervision) to share and compare experience in paint binders analysis.
  2. Secondment period of 4 months at The British Museum (UK).
  3. Secondment period of 2 months at the conservation section of the Ny Carlsberg Glyptotek (NCG) to optimise, together with curators and restorers, the most effective and less invasive sampling procedure. Sample collection will take place in close collaboration with the conservation section of the NCG.

Regular interaction with Patrick Rüther, also based at UCPH, will be aimed at implementing the analytical improvements Patrick will develop as part of his research and development project.

Investigation of samples shared with Francesca Galluzzi's project (@USTL), also shared with UCAS, to contrast with pigment investigations on materials in China.

At: University of Copenhagen

Supervisor: Enrico Cappellini

Photo credits: Fabiana Di Gianvincenzo