0000000000171932
AUTHOR
Howell G. M. Edwards
showing 5 related works from this author
An authentication case study: Antonio Palomino versus Vicente Guillo paintings in the vaulted ceiling of the Sant Joan del Mercat church (Valencia, S…
2012
In 1695, the Valencian artist Vicente Guillo was engaged in painting the vault of the Sant Joan del Mercat church in Valencia, Spain. After preliminary work was carried out, his contract was cancelled. In 1697, Antonio Palomino, renowned for the publication of his technical treatise entitled El Museo Pictorio y Escala Optica, was finally selected as the painter in charge of decorating the vaulted ceiling of Sant Joan del Mercat. This paper reports an analytical study focused on the characterisation and discrimination of the palette and painting procedures used by Palomino and Guillo in the frescoes of Sant Joan del Mercat. For this purpose, Raman spectroscopy combined with light microscopy,…
On the interpretation of the Raman spectra of Maya Blue: a review on the literature data
2011
The Raman spectroscopy of Maya Blue (MB), a nanostructured organic–inorganic hybrid material, has received considerable attention. A re-evaluation of the Raman literature data for indigo dye, genuine MB samples and model specimens obtained by the binding of indigo to phyllosilicate clays, such as palygorskite and sepiolite, using chemometric analysis of normalised spectra is reported. Available data present features in support of the following ideas: (1) dehydroindigo accompanies indigo in MB; (2) different topological isomers, i.e. dye molecules attached to different coordinative sites of the palygorskite framework, are involved in MB; and (3) different procedures were probably used for pr…
Composition and Color of Maya Blue: Reexamination of Literature Data Based On the Dehydroindigo Model
2019
[EN] An analysis of literature data studying the composition and color of Maya blue (MB) type materials prepared from indigo, dehydroindigo, and different aluminosilicates, accompanied by new spectral data, is presented. After thermal treatment at above 100 degrees C, indigo-based specimens displayed Raman and UV-vis spectroscopic features common to those of equivalent dehydroindigo-based replicants, thus supporting the socalled dehydroindigo model (J. Phys. Chem. B 2006, 110, 6027-6039) in which the dehydroindigo/indigo ratio, increasing with temperature, is crucial to determine the color of MB and its variability. The current analysis supports the view of MB as a polyfunctional hybrid mat…
Identification of Earth Pigments by Applying Hierarchical Cluster Analysis to Solid State Voltammetry. Application to Severely Damaged Frescoes
2007
Multivariate chemometric methods are applied for identifying earth pigments from square-wave voltammetric measurements performed at pigment-modified paraffin-impregnated graphite electrodes allowing for a separation between hematite-based earths, French ochres, Spanish ochres, siennas, umbers and green earths. This methodology is applied to the identification of the pigments in samples from the ceiling frescoes of Antonio Palomino (dated 1707) in the vaulted nave of the Sant Joan del Mercat church in Valencia (Spain). These frescoes suffered considerable damage by fire during the Spanish Civil War in 1936, resulting in severe chemical and chromatic alterations. Electrochemical data, support…
A Raman spectroscopic and combined analytical approach to the restoration of severely damaged frescoes: the Palomino project
2008
The deterioration of art objects is normally relatively minor, controllable and attributable to environmental changes or bacterial invasion, and until now there has not been any recorded attempt to analyse an artwork that has been deliberately and significantly destroyed. The analytical problems are correspondingly larger but the potential reward from any information that can be forthcoming is thereby proportionately greater. The 17th Century Palomino frescoes on the vaulted ceiling of the Church of Sant Joan del Mercat in Valencia were largely destroyed by insurgents in the Spanish Civil War in 1936. The ensuing gunfire and a series of seven conflagrations inside the church had a devastati…