This dissertation is an account of an internship in painting conservation undertaken at the Auckland City Art Gallery during the period January to August 1983. It has been divided into three parts with six associated appendices. Part one discusses the functions and facilities of the Conservation Department. The functions being classed into two main categories, that concerned with the Auckland City Art Gallery and that concerned with National Conservation. The facilities of the Department are not only the equipment and materials of the Conservation studios but the equipment and design around the Gallery that facilitate the task of the conservators whether it be through treatment or by preventative means. Part two covers the programme of work carried out. As indicated in Part one, the conservation department has many other functions apart from the treatment of works of art, and as a member of the department during my internship, I was involved in a number of these which are discussed in this section. This includes packing, meetings and visits to other institutions. Part three deals with the conservation treatments carried out. Section one summarizes the methods and materials used, section two lists the works treated in the order that they were begun, and section three covers the condition and treatment reports for each work. Finally, six appendices have been included which augment information in the text such as a description of the present renovations to the Auckland City Art Gallery and a brief history of conservation in New Zealand.

My employment in the Paintings Section of the Conservation Department of the Australian National Gallery began in June 1983, however my internship did not begin until March 1984 under the supervision of Allan Byrne. At that time, the paintings section was divided, rather arbitrarily, into: paintings pre-1940, headed by Ilse King and; paintings post-1940, headed by Allan Byrne. Because of the departure of the then senior curator of conservation Dr Nathan Stolow, Allan Byrne became acting senior curator. When Allan Byrne took up the position of lecturer in paintings conservation at C.C.A.E., Ilse King then became acting senior curator and my supervisor; the division within the painting section was then disbanded. Jac Macnaughtan departed temporarily from the department to undertake study and to work at the Tate Gallery and at the Courtauld Institute in London leaving me with the paintings section. I was fortunate enough to have at first one assistant Simon Hartas, then two assistants, Mark Henderson and Les Cormack to help with the task of backing, framing and restretching paintings. There was no formal training programme for an intern - work was undertaken as it came into the department and as it was allotted. For the sake of simplicity and ease of handling the dissertation is divided into 3 parts: Part 1 includes the Functions and Facilities of the conservation department. Part 2 includes an outline of painting conservation practice within the gallery and details of conservation work undertaken. Part 3 comprises a project on some of the properties of hardboard. As the gallery has in its collection a considerable number of paintings on hardboard, to augment my knowledge and perhaps give some insight into the nature of hardboard, this project was undertaken in conjunction with the internship.

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Indiana University-Purdue University Indianapolis (IUPUI) / Finely-tuned solvent mixtures are used by art conservators for the difficult task of safely and selectively removing yellowed varnish, disfiguring grime, and discolored overpaint from the surface of oil paintings. This process is often referred to as “picture cleaning” and depends on the different solubilities of the obfuscating surface materials and the underlying paint medium. However, differential evaporation rates for the solvents used in these carefully formulated cleaning mixtures can change the potency of the mixture over time, which could potentially lead to solutions having solubility characteristics that are ineffective at cleaning, or worse yet, are deleterious to artists’ oil paints. Azeotropic blends of solvents have been proposed as an alternative for maintaining consistent solvent composition throughout the evaporation process while benefiting from their high vapor pressure relative to the pure solvents. Azeotropes are specific combinations of two or more solvents at a precise concentration that behave as a single solvent, maintaining a constant composition in both the liquid and vapor phases. The use of purportedly azeotropic solvent blends has appeared in the art conservation literature for the cleaning of historic objects and paintings. However, these solvent mixtures are taken from tables of azeotropic compositions given at their boiling point. We have studied one of these solutions, a 19:81 vol% mixture of isopropanol and n-hexane. For the first time, the actual evaporation behavior of this purported azeotropic mixture was followed in detail at room temperature conditions. Through the use of rudimentary vapor pressure measurements, gravimetric analysis, as well as sophisticated compositional determinations of both the liquid phase and headspace of evaporating mixtures by gas chromatography, this particular cleaning solution has been shown to be zeotropic (i.e. NOT an azeotrope) under the conditions typical of conservation studios. The true room temperature azeotropic composition was found instead to contain half as much isopropanol at 9.5 vol%. Art conservators should therefore be dubious of purportedly azeotropic mixtures reported at boiling points well above room temperature. Individual azeotropic cleaning blends are best determined chemically prior to their use in art restoration. Furthermore, the introduction of a model paint film to the evaporating room temperature azeotrope was shown to further confound its behavior, calling into question whether solvent systems can be configured to evaporate with constant composition from the surface of an artwork.