To meet a variety of needs in information modeling, software development and integration as well as knowledge management and reuse, various groups within industry, academia, and government have been developing and deploying sharable and reusable models known as ontologies. Ontologies play an important role in knowledge representation. In this paper, we address the problem of capturing knowledge needed for indexing and retrieving art resources. We describe a case study in which we attempt to construct an ontology for a subset of art. The aim of the present ontology is to build an extensible repository of knowledge and information about artists, their works and materials used in artistic creations. Influenced by the recent interest in colours and colouring materials, mainly shared by French researchers and linguists, an ontology prototype has been developed using Protégé. It allows to organize and catalog information about artists, art works, colouring materials and related colours.