Dual mode standoff imaging spectroscopy documents the painting process of the Lamb of God in the by J. and H. Van Eyck.

The ongoing conservation treatment program of the by Hubert and Jan Van Eyck, one of the iconic paintings of the west, has revealed that the designs of the paintings were changed several times, first by the original artists, and then during later restorations. The central motif, The Lamb of God, representing Christ, plays an essential iconographic role, and its depiction is important. Because of the prevalence of lead white, it was not possible to visualize the Van Eycks' original underdrawing of the Lamb, their design changes, and the overpaint by later restorers with a single spectral imaging modality.

Large-Area Elemental Imaging Reveals Van Eyck's Original Paint Layers on the Ghent Altarpiece (1432), Rescoping Its Conservation Treatment.

A combination of large-scale and micro-scale elemental imaging, yielding elemental distribution maps obtained by, respectively non-invasive macroscopic X-ray fluorescence (MA-XRF) and by secondary electron microscopy/energy dispersive X-ray analysis (SEM-EDX) and synchrotron radiation-based micro-XRF (SR μ-XRF) imaging was employed to reorient and optimize the conservation strategy of van Eyck's renowned Ghent Altarpiece. By exploiting the penetrative properties of X-rays together with the elemental specificity offered by XRF, it was possible to visualize the original paint layers by van Eyck hidden below the overpainted surface and to simultaneously assess their condition. The distribution of the high-energy Pb-L and Hg-L emission lines revealed the exact location of hidden paint losses, while Fe-K maps demonstrated how and where these lacunae were filled-up using an iron-containing material.

Characterisation of the rare cadmium chromate pigment in a 19th century tube colour by Raman, FTIR, X-ray and EPR.

In an investigation of the artists' materials used by P. S. Krøyer the contents of the tube colours found in Krøyer's painting cabinet were examined.

Raman analysis of complex pigment mixtures in 20th century metal knight shields of the Order of the Elephant.

The pigment composition of six painted metal knight shields of the Order of the Elephant dating from the second half of the 20th century belonging to the Danish royal collection were studied using Raman microscopy. By focusing a 785 nm laser with a 50× objective on particles in paint cross sections, it was possible to identify the following 20 compounds: hematite, goethite, chrome red/orange, chrome yellow, zinc chrome yellow, carbon black, toluidine red PR3, chlorinated para red PR4, dinitroaniline orange PO5, phthalocyanine blue PB15, indanthrone blue PB60, ultramarine, Prussian blue, lead white, anatase, rutile, calcium carbonate, barium sulphate, gypsum and dolomite. The components were frequently present in complex pigment mixtures.

Analytical study of modern paint layers on metal knight shields: the use and effect of titanium white.

Painted metal knight shields of the Order of the Elephant produced during the last part of the 20th century are characterized by a striking variety in their conservation state. Three different coat systems were identified and investigated by Fourier transform infrared microscopy (μ-FTIR), micro-Raman spectroscopy (MRS), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX) and Thermally assisted hydrolysis and methylation-gas chromatography-mass Spectrometry (THM-GC-MS). Chalking of the white paint layer on the first group of knight shields displayed in the window niches was found to be related to the use of titanium white of the anatase type.

Synthesis and fading of eighteenth-century Prussian blue pigments: a combined study by spectroscopic and diffractive techniques using laboratory and synchrotron radiation sources.

Prussian blue, a hydrated iron(III) hexacyanoferrate(II) complex, is a synthetic pigment discovered in Berlin in 1704. Because of both its highly intense color and its low cost, Prussian blue was widely used as a pigment in paintings until the 1970s. The early preparative methods were rapidly recognized as a contributory factor in the fading of the pigment, a fading already known by the mid-eighteenth century.

Development of a dedicated peptide tandem mass spectral library for conservation science.

In recent years, the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) on tryptic digests of cultural heritage objects has attracted much attention. It allows for unambiguous identification of peptides and proteins, and even in complex mixtures species-specific identification becomes feasible with minimal sample consumption. Determination of the peptides is commonly based on theoretical cleavage of known protein sequences and on comparison of the expected peptide fragments with those found in the MS/MS spectra.

Striking presence of Egyptian blue identified in a painting by Giovanni Battista Benvenuto from 1524.

Egyptian blue has been identified in a painting from 1524 by the Italian artist Ortolano Ferrarese (Giovanni Battista Benvenuto). Egyptian blue is the oldest known synthetic pigment, invented by the Egyptians in the fourth dynasty (2613-2494 BC) of the Old Kingdom and extensively used throughout Antiquity. From about 1000 A.

Classification of protein binders in artist's paints by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry: an evaluation of principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA).

Proteomics techniques are increasingly applied for the identification of protein binders in historical paints. The complex nature of paint samples, with different kinds of pigments mixed into, and degradation by long term exposure to light, humidity and temperature variations, requires solid analysis and interpretation methods. In this study matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectra of tryptic-digested paint replicas are subjected to principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA) in order to distinguish proteinaceous binders based on animal glues, egg white, egg yolk and milk casein from each other.

Unexpected materials in a Rembrandt painting characterized by high spatial resolution cluster-TOF-SIMS imaging.

The painting materials of the Portrait of Nicolaes van Bambeeck (Royal Museums of Fine Arts of Belgium, Brussels, inv. 155) painted by Rembrandt van Rijn in 1641 has been studied using high resolution cluster-TOF-SIMS imaging. In the first step, a moderate spatial resolution (2 μm) was used to characterize the layer structure and the chemical composition of each layer on account of a high mass resolution.

Tryptic peptide analysis of protein binders in works of art by liquid chromatography-tandem mass spectrometry.

A proteomics approach was used for the identification of protein binders in historical paints: the proteins were digested enzymatically into peptides using trypsin before being separated and detected by high performance liquid chromatography-electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS). Mascot (Matrix Science) was used to analyse the resulting data and for protein identification. In contrast to amino acid analysis, amino acid sequences could be studied that retain much more information about the proteins.

Identification of protein binders in works of art by high-performance liquid chromatography-diode array detector analysis of their tryptic digests.

Proteins in works of art are generally determined by the relative amounts of amino acids. This method, however, implies a loss of information on the protein structure and its modifications. Consequently, we propose a method based on the analysis of trypsin digests using high-performance liquid chromatography (HPLC) UV diode array detection (DAD) for painting binder studies.