Fourier Transform Infrared Microscopic Imaging of an Embedded Paint Cross-Section

Abstract

Fourier transform infrared imaging is presented as a new analytical approach in the study of paint cross-sections. Analytical FT-IR reflection imaging provides the spatially resolved acquisition of infrared spectra with a resolution of about 7 μm. The technique reveals detailed information on the organic functional group distribution in the individual layers of embedded paint cross-sections and is used complementary to visual microscopy and scanning electron microscopy/energy dispersed X-ray spectroscopy (SEM-EDX). This method was applied to a paint cross-section of Rembrandt's Portrait of a Standing Man (1639). FT-IR imaging of this cross-section identified and localized different compounds present in the layers of this sample. Identification of these compounds based on their infrared spectra is confirmed by results from art historical and conservation literature. Special attention was given to a discoloration that was observed in large parts of the described painting. This discoloration was clearly visible in the paint cross-section. A hypothesis on the nature of the discolored paint layer is formulated based on the FT-IR imaging results.

The role of SIMS in cultural heritage studies

“…This capability has been demonstrated in work by Van der Weerd et al [3], which focuses on the deterioration of lead pigmented paint layers. Small crater like holes or protrusions which are present across the entire surface of The Anatomy Lesson of Dr Nicolaes Tulp (Rembrandt van Rijn, 1632), have been the subject of many studies.…”

“…if the analyte species is a molecular ion containing two atoms then the matrix species should be similar). Then the concentration C X of impurity X in the unknown sample can be determined from À13 and 3 · 10 À12 cm 3 , and that of SSIMS imaging is between 3 · 10 À18 and 3 · 10 À16 .…”

“…In the area of art and archaeometry, SIMS has been applied successfully to a wide range of materials, including pigments [2,3], glasses [4][5][6][7][8][9][10][11][12][13], metal alloys and tarnishes [14][15][16][17], and human remains such as teeth [18]. Here we describe in more detail the use of both dynamic and static SIMS for some selected applications.…”

“…SIMS revealed also the presence of chlorine in the protrusions. The reason for its presence is somewhat unclear but the hypothesis is that it could be a normal contamination of 17th century lead white, because the production process is far from well defined [3]. Recent surveys have shown that the occurrence of protrusions is much more common than first thought and has been observed in paintings from the 15th through 20th century and seems to be a common defect in oil paintings [22].…”

Feasibility of analyzing molecular pigments in paint layers using TOF S–SIMS

“…It therefore represents one of the few methods capable of closing the traditional gap between the fields of organic and inorganic analytical chemistry. This capability has been demonstrated in work by the research group at AMOLF [10][11][12] for the study of paint crosssections.…”