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 055 5225483
Institute for the Conservation and Valorization of Cultural Heritage