Doc. No. 4110-0030 Rev. B Page 1 of 2 Effective Date: 5-Dec-2006
Application Note
Visualization of Under-drawings
in the Near-Infrared (NIR)
Spectrum
Goodrich’s SUI (Sensors Unlimited, Inc.) team
has applied its solid-state Indium Gallium
Arsenide camera to the fields of art history and
conservation. Non-invasive (remote)
examination of art objects including paintings,
manuscripts, textiles, etc., can be easily
accomplished in the Near Infrared (NIR)
spectrum with the model SU320-1.7RT. Many
paints that are reflective in the visible spectrum
are transparent in the NIR. The SU320-1.7RT
“sees” through the paint and images the “under-
drawing”.
Numerous artists composed a preliminary
sketch on a canvas or wood panel. The outline
drawing is done with a soot/charcoal substance,
which is highly reflective in the NIR spectrum.
This drawing could be changed if the artist didn’t
like the result. In the finished painting these
outlines were covered by the paint, and thus
invisible.
The science of Infrared Reflectometry (IRR) with
SUI’s solid-state detector technology has helped
to understand the style and techniques of
numerous artists. Renoir’s “Luncheon of the
“Boating Party” at the Phillips Collection,
Washington, DC was examined with the use of
IRR to show what was “invisible” to the “naked”
eye.
The SU320-1.7RT has both a video output for
direct interface to standard monitors and VCRs
and a digital output for integration into a
customer’s computer. The camera is superior to
any other solid-state or vacuum tube in the NIR
spectrum. It is lightweight, easily transportable,
requires no cooling, and does not exhibit defects
such as image lag, persistence, blooming, low
damage threshold, or tube wear-out.
The images below show an oil painting of
sunflowers as viewed with a visible CCD camera
(on the right) and in the NIR with a SU320-
1.7RT (on the left). Please call SUI to have a
demonstration at your site.
Doc. No. 4110-0030 Rev. B Page 2 of 2 Effective Date: 5-Dec-2006
If you need further technical support, please
contact our sales department via email
sui_support@goodrich.com or call us at
609-520-0610.
About Goodrich’s SUI Team: Founded in 1991,
SUI (Sensors Unlimited, Inc.) is the leading
manufacturer of indium gallium arsenide
(InGaAs) PIN and avalanche photodiode arrays
that are used in shortwave and near infrared
imaging for military, industrial, spectroscopic,
machine vision, and telecommunications
applications. SUI provides InGaAs photodiode
array processing as a foundry service and
designs custom readout integrated circuits for
unique imaging applications within its ISO 9001
certified facility. For more information, visit
www.oss.goodrich.com/sui.