Fiber Optic Reflectance Spectroscopy (FORS)
Analytical technique
description

The application of FORS is mainly addressed to the identification of pigments, dyes, alteration products and to the analysis of the color coordinates and their variations. It’s a totally non-invasive technique and thanks to the portable equipment, allows in-situ measurements.
Applications
Directly in-situ on paintings, frescoes, stone materials, carvings wood and in general on polychrome artifacts.
Basics
It is based on the analysis of reflectance spectra in which the intensity of the radiation backscattered from the investigated surface is reported as a function of the wavelength of the incident radiation. The intensity’s value, reported as percentage of scattered (reflected) light from the investigated surface, is compared to a reference white, assumed diffusing at 100% the light throughout the spectral range considered. The identification of the pigments is carried out for comparison with spectra of reference mock up paintings.
Instrumental details
Spectral ranges 350-900nm, 900-2100nm
Spectrometer Ocean Optics HR2000 (CCD array)
(Florence Unit, Milan Unit).
Spectrometer Ocean Optics NIR256 (256 InGaAs linear-array)
(Florence Unit).
Deuterium light source DH-2000 (210-400nm)
(Florence Unit).
Tungsten light source HL-2000-FHSA (360-2400 nm)
(Florence Unit, Milan Unit).
The instrument is equipped with fiber optic bundles and different probes.
ICVBC - AREA DI RICERCA CNR DI FIRENZE
Via Madonna del Piano, 10 - 50019 Sesto Fiorentino (FI)
Tel. 055 5225484 - Fax 0555225403
Email: sede@icvbc.cnr.it
Institute for the Conservation and Valorization of Cultural Heritage