Norman H. Tennent

The deterioration and conservation of painted glass : a critical bibliography

Bibliography of papers bearing on conservation of painted glass. One hundred twenty nine entries. Recovery of lost faded decoration on painted glass. Use of the isoprobe for studying the chemical composition of some twelfth century glass from York Minster. A study of cleaning painted and enamelled glass in an ultrasonic bath.

The mode of formation of thecotrichite, a widespread calcium acetate chloride nitrate efflorescence

Abstract The widespread occurrence of thecotrichite, Ca3(CH3COO)3Cl(NO3)2·7H2O, in the museum environment is explained theoretically by construction and examination of its phase diagram. Thecotrichite formation was simulated in the laboratory to identify the key factors involved in its production. This efflorescence occurs on porous limestone or calcareous artefacts such as pottery, stored in wooden cabinets that generate acetic acid vapour. Salt production depends on the moisture content of the object and the concentration of acetic acid in its surroundings. Furthermore, for thecotrichite to form the artefact must contain soluble chloride and nitrate salts.

Dicalcium triacetate nitrate dihydrate

The structure of tri-mu-acetato-diaqua-mu-nitrato-dicalcium [Ca-2(CH3COO)(3)(NO3)(H2O)(2)](n), is shown to consist of infinite O-bridged double-stranded calcium chains crosslinked both by bridging anions and by hydrogen bonding to form a three-dimensional polymer. Both the independent Ca centres are eight-coordinate.

Some Applications of Ion Chromatography to the Study of the Deterioration of Museum Artifacts

Ion chromatography has been applied to the investigation of corrosion and efflorescence products on a range of museum artifacts whose deterioration is due to reaction with organic carbonyl pollutants in the storage environment. The potential of the technique and its optimisation for the determination of chloride, acetate, formate, nitrate and sulphate anions and associated cations are reported. Compounds containing acetate and/or formates from ceramic, geological, mollusca and metal collections have been investigated. The utility of ion chromatography for the examination of specimens which show no visible efflorescence, but from shich significant acetate and formate levels can be quantified, is also demonstrated. The complementarity of ion chromatography and other techniques, in particular X-ray diffraction and infra red spectroscopy, for the investigation os efflorescence products is emphasised. -- CAL

APPLIQUÉ STAINED GLASS: THE CONFLICT BETWEEN CONSERVATION AND CONTEXT

Abstract Four major British stained glass commissions are discussed, made in the 1960s by the appliqué technique. This involved bonding coloured glass to plate glass with an adhesive, epoxy resin in each case. The examples reported comprise the lantern glass of Blackburn and Sheffield Cathedrals, the baptistry glass of St John the Evangelist Church, Eastbourne, and the Churchill Memorial Screen in Dudley, in an outdoor community precinct. In all cases, the glass-to-glass bond began to fail within a few years. Now, none of these creations remains in situ. Conservation was either deemed unrealistic or, in the case of the Churchill Memorial Screen, proved unsatisfactory. Its few remaining panels have been in storage for many years with no plans for redisplay. This paper examines the context for these appliqué stained glass creations and how the available expertise was insufficient to bring about successful conservation schemes. Documentation, written or oral, from the original glass artists, architects, church and local authorities, adhesive manufacturers and conservation consultants is presented. The decision-making process is reviewed with respect to this evidence, notably the inadequate technical knowledge available at the time.