The Challenge:
Conservators and researchers are always looking for non-destructive and easy-to-use techniques to assist with art conservation projects. Examples include the discrimination of pigments, detection of under-drawings, study of varnishes and binding material, forgery detection and other analytical techniques.

The Solution:
Optical spectroscopy in the visible and infrared regions provides a number of non-destructive analysis tools. An imaging system comprised of a VariSpec tunable filter, CCD camera, objective lens and quartz-halogen lights was assembled into a portable format for simple imaging of artwork in the gallery. A data cube was collected through the visible to near-infrared region in approximately 10 nm increments. The data was transferred to ENVI for analysis.

The Tools Used:
SNIR VariSpec liquid crystal tunable filter (650 - 1050 nm)
Hamamatsu CCD camera
Nikon 35 mm lens
Laptop computer
ENVI software

The Difference It Made:
Near-infrared spectroscopic imaging of artwork has proven to reveal under-drawings more clearly and distinguish differences in chemical composition between the various materials used to make the drawing. The imaging system is portable and easy to set up and use. The image collection is fast and the entire process is well received by art conservators.

1040 nm: Graphite    Images courtesy of M. Attas	850-875 nm: Iron Oxide	730-850 nm: Iron Oxide