Susan Stock

Summary-A new pale blue corrosion product has been found on copper alloy artifacts in the collections of a number of institutions. The corrosion product has been characterized using X-ray powder diffraction, X-ray photoelectron spectroscopy, wavelength X-ray dispersive ...

... many artefacts cannot be considered for sampling because of their value (aesthetic or monetary); condition; or ... Detail of firescale (image repro-duced courtesy S. Stock) ... Indeed in Roman times, in Pompeii, Egyptian blue (cuprorivaite) was called Pompeian blue or caeruleum. ...

The original Centre Block on Parliament Hill (Ottawa, Canada) (designed in 1859) was destroyed by fire on the night of February 3, 1916. The Library of Parliament (completed in 1877) remained standing after this fire, and its original structure was intact until another fire occurred in the dome in 1952. This event necessitated significant alterations over the next 4 years, and these affected the heritage fabric, design and character of the building. This document describes a recent conservation examination and analysis of architectural features and coatings on the interior and exterior of the Library of Parliament. The purpose of the examination and analysis was to document and characterize the materials that were used in both the original construction and the later renovations. The study established a baseline reference for the materials used and their present condition, which will assist in the development of treatment protocols.

Four iron statues dated by inscription to the Ming Dynasty, China, (1491 A.D.) were investigated for their metal composition and coating structures. The investigation was initiated with the intent of ascertaining whether any prior treatment had been done and to determine the present condition of the object. During visual examination and simple surface cleaning, it became apparent that the objects had some form of surface decoration and polychrome. On closer examination, gilding, lacquer, and traces of pigment around the hat, eyes, and garment were visible. A sample of the metal was taken for metallography and chemical compositional analysis. Samples were taken from the surface of the four objects to identify the composition of the observed decoration and corrosion. The results revealed that the statues are white cast iron and were fully decorated with multiple colours and gilding as well as being sequentially lacquered. Recommendations for the cleaning and conservation of these obje...

The object was brought to the ROM conservation labs for cleaning and repair, as the decorative detail was obscured by corrosion overburden and some of the cloisons were loose. During further microscopic examination and mechanical cleaning, an unusual decorative metal inlay technique was revealed. Metal inlays of the period tended to be flat pieces of foil or leaf placed into the decorative pattern over a metal substrate, and typically one of several techniques could be used to hold the inlay in place, including an organic or inorganic adhesive, or keying of the metal substrate itself. In an area of loss around the expected tiny punch-work domes of repoussé work, it became clear that the silver-like metal inlay was actually constructed from rods packed vertically into the space which formed the 'inlay'. Removing corrosion overburden confirmed this unique feature. Description: The belt hook is finely crafted of gilt copper alloy (bronze), covered with inlaid turquoise and a form of filigree (silver wire) forming cloisons along the body. The animal head finial is covered in gold foil with bead eyes. Radiography suggests that the finial may have been added onto the bronze body, but further investigation is required to confirm this. Inset around the turquoise and cloisons are areas representative of repoussé.