FORS

Fiber Optics Reflectance Spectroscopy (FORS) is a non-invasive analytical technique widely used in art conservation and archaeology to identify and characterize surface materials through their optical response to light. The method measures the reflectance of an object across the ultraviolet, visible, and near-infrared spectral ranges using fiber-optic probes, allowing rapid, contact-free or near-contact analysis of culturally significant objects.

In the field of art examination, FORS is especially valuable for the identification of pigments and dyes in paintings, manuscripts, polychrome sculpture, and decorative arts. Many colorants display diagnostic absorption bands or spectral inflection points that can be recognized even in complex mixtures or thin glaze layers. Because FORS does not require sampling, it is ideally suited for fragile or unique artworks where invasive analysis is not permitted.

In archaeology, FORS enables the in situ study of painted surfaces, ceramics, stone artifacts, and architectural remains, helping to distinguish original materials from weathering products, burial alterations, or later restorations. Portable instrumentation makes the technique practical for both museum collections and archaeological sites.

While FORS does not provide elemental composition, it delivers precise optical information that complements techniques such as X-ray fluorescence (XRF), Raman spectroscopy, and technical imaging. When integrated into a multi-analytical workflow, FORS significantly enhances material interpretation, supports conservation decision-making, and deepens understanding of artistic technologies and archaeological materials while fully preserving the integrity of cultural heritage objects.