SOME ASPECTS OF THE CONSERVATION OF WAX MODELS

Abstract

During the Italian Renaissance wax was used to produce polychrome relief portraits on a miniature scale. This use of wax as a material for finished sculpture was subsequently adapted to the production of tableaux, of anatomical models, of life-size wax-works and of wax dolls. This article gives a brief account of the techniques of this type of sculpture and describes problems of conservation and restoration. Methods of repairing, cleaning and restoration are discussed, and the article concludes with a full account of the restoration work carried out on an allegorical tableau by Gaetano Zumbo and on two 17th-century ecclesiastical dolls.     

A PRELIMINARY NOTE ON THE USE OF ADHESIVES AND FILLERS IN THE RESTORATION OF ANCIENT MATERIALS WITH SPECIAL REFERENCE TO GLASS

Abstract

We have reacted Georgia marble in sulfur dioxide (SO₂) enriched atmospheres and calculated the reaction rate constant. This constant was derived from surface reduction data, obtained by leaching thereaction product from samples exposed for different periods of time. Application of this constant to marble weathered in known ambient levels of sulfur dioxide (SO₂) and relative humidity, allows the prediction of the thickness of the resulting gypsum crust formed over a given period of time. We have found that the crust grows outwards due to calciumions which migrate from the interior and then react with sulfur dioxide at the sample surface. Thus, anytreatment of the sulfated marble should include the considerations that the crust only masks the marble surface and is not an integral part of the original sculpture, and that cavities exist in the underlying layer of marble from which the calcium ions were selectively depleted.     

A NOTE ON THE CLEANING OF SHELL INLAY ON ETHNOGRAPHICAL SPECIMENS FROM OCEANIA

Abstract

Problems were encountered when preparing objects from the Pacific islands for exhibition. These specimens were of wood with shell inlay. Cleaning with non-ionic detergent and distilled water had no effect on the dull shell surface; solvents were little better;finally, glass fibre brushes were tried with very good results. Precautions should be taken when using glass fibre brushes; these include the wearing of protective gloves, dust masks, and the provision of a vacuum cleaner to remove fragments of broken glass fibre and dust from the shell surface.     

THE SCIENTIFIC EXAMINATION OF THE POL YCHROMED SCULPTURE IN THE HERLIN ALTARPIECE

Abstract

An account is given of the examination of the polychromed sculpture in the Hedin altarpiece (1466) in Rothenburg old T. (W Germany). Analytical methods used, such as microscopy, wet chemical analysis, infrared spectrophotometry, thin-layer chromatography and gas-liquid chromatography are briefly described. Criteria for identification are summarized. Pigments identified are azurite, indigo, verdigris, green earth, madder, vermilion, red lead, lead white and carbon black. The binding medium is glue in matt areas. In other parts paints are mostly based on a resinous medium with varying amounts of oil. The materials identified in the applique relief brocades are compared with recipes described in the Liber Illuministarius from Tegernsee. Silver foil is used in producing translucent paint.     

POLYCHROMED SCULPTURES IN JAPAN

Abstract

Japanese sculptures are made of wood, dry lacquer, clay, gilt bronze and stone. Buddhistic statues, made of wood, are the most abundant. The painting techniques of the wooden sculptures, including ground coating, pigments, and application of Japanese lacquer, are described, and typical examples of Buddhistic statues are given. Specific case studies on a clay statue and a wooden sculpture are made.     

ON THE OCCURRENCE OF BROMINE IN CORRODED SILVER

Abstract

Attention is drawn to the finding of silver bromide as a regular corrosion product on buried ancient silver. The chemical processes leading to this, and their relation to the burial environment, are discussed.     

THE USE OF AN INFRA-RED IMAGE-CONVERTER FOR THE EXAMINATION OF PANEL PAINTINGS

Abstract

The use of an S-1 response infra-red image-converter for the examination of panel paintings is described. It is shown that satisfactory results maybe obtained with this equipment, which is easy to operate. The examination of underdrawings, retouchings and pentimenti is briefly discussed.     

ON THE CONSERVATION OF THE BAPTISTERY DOORS IN FLORENCE

Abstract

The causes of deterioration of the gilded bronze doors of the Baptistery in Florence have been examined and the mechanism of corrosion discussed. An apparatus for thermal conditioning has been proposed and tested either on the north door of the Baptistery, or on samples exposed to the urban atmosphere in Milan and by laboratory tests on an electrochemical model. The effectiveness of the proposed apparatus has been verified by weight losses, by assessing soluble salts, by visual observations, by local chemical microanalyses, by morphological examinations with a scanning electron microscope equipped with an X-spectrometer and by X-ray diffraction.     

THE CONSERVATION OF TAPESTRIES FOR MUSEUM DISPLAY

Abstract

A broad outline of the considerations which arise with regard to the conservation of a museum collection of tapestries is given in this paper. The various types of damage to, and deterioration of, tapestries is discussed.

Various methods of washing and dry cleaning, and the equipment necessary for these procedures, are reviewed, and a caution is included as to the necessity of testing all dyes for colour fastness in both water and any solvent used for dry cleaning. The equipment, materials and techniques of repair are discussed; three methods of repair being currently used in museums and specialist workshops — re-weaving, stitching on to a backing and the use of synthetic resins for impregnation and adhesion to a woven support. It is suggested in conclusion that the optimum method of repair in museums is stitching on to a backing. More research must be undertaken into the use of synthetic resins, and re-weaving usually alters the original appearance of the tapestry.

Finally, the need for specialised conservation staff in a museum with a tapestry collection is emphasised.     

NOTES ON THE USE OF A VACUUM HOT-TABLE FOR TEXTILES

Abstract

A miniature low-pressure apparatus for localized treatment of paintings is described. Alternative working surfaces are available which allow heat and moisture treatment on canvas paintings without removal from their stretchers. Other applications of the apparatus are discussed.     

NOTES ON THE CONSERVATION OF SCULPTURE,STONE, MARBLE AND TERRACOTTA

Abstract

Sulphuration is the main destroyer of marble, producing imaginary (not true) patina. Other reasons for the discoloration of marbles are discussed. Magnesium silicate saturated with de-ionized water is a safe and simple cleaner. Sintolite is advocated as an adhesive for marble rather than the general more fluid epoxy resins. Solid polyvinyl acetate is strongly advocated as the basis for sma1l repairs to internaIly housed marble. The consolidation of marble is discussed and a method for internal exhibits recommended. Conservation of unbaked clay is touched upon, and a method for the repair of terracotta suggested together with a process for the reproduction of a glazed frieze using a latex mould and epoxy-reinforced plaster casts. A few remarks are made concerning the dangers of cleaning alabaster with water. The commentary is of a general nature and is not intended as a strict blueprint for any particular object.     

THE VIRGIN AND CHILD FROM THE CHURCH OF DAL (NORWAY)—EXAMINATION AND RESTORATION

Abstract

A polychromed sculpture was restored and examined. The shrine is made from pine-wood and the sculpture from oak. The ground consists of chalk and animal glue; the pigments are: azurite, a green copper pigment, yellow organic colouring material, orpiment, red lead, vermilion, red organic colouring material, iron oxide red, lead white and charred matter (charcoal ?). Metals used are gold and silver. The medium is on a drying-oil base to which a protein-containing material is added. Generally, the colours were built up in two layers. There is an extensive use of imitation gold, while the use of gold foil is limited to the areas of hair and the flowers on the garments.

In general, the wood in all parts of the object was in good condition and no general impregnation was needed. Cracks in the shrine were filled in with wood or rejoined. The sculpture, which was split in two, was glued together. The condition of the polychromy was relatively good, and only local treatment was required.     

ON THE CHOICE OF PAPER FOR LINING WORKS OF ART ON GROUND WOOD PULP SUPPORTS

Abstract

Measurements on the rectangular oak supports to three portraits, which include those of Henry VII and of Henry VIII, indicate they were made from the same tree and enable the approximate date at which the panels were used to be determined by dendrochronology. There is the likelihood that a fourth member of the group, previously believed to be Arthur, Prince of Wales, is a copy of an early portrait of Henry VIII.     

DECREASING THE YELLOWING RATE OF DAMMAR VARNISH USING ANTIOXIDANTS

Abstract

The use of antioxidants to retard the yellowing rate of dammar varnish is investigated. A dammar formulation is given which should not significantly yellow in two to three hundred years of natural ageing. It is also shown that the choice of solvent when preparing a dammar varnish solution will affect yellowing rates of the resulting films.     

POLYCHROME SCULPTURE IN SWEDEN

Abstract

A survey is given of polychromed sculpture in Sweden. Historical aspects of the care of sculptures are discussed. Many retables have been imported from Lübeck and Antwerp. Polychromed sculptures are often well preserved because there was hardly any iconoclasm in Sweden. Many need treatment however due to various forms of neglect. A special case—the triptych of Kärrbo (c. 1500)—is described in detail from a technical point of view.     

Examination and treatment of a seventeenth-century Spanish polychrome sculpture by Jose Caro

Abstract

The sculpture of St Gines de la Jara in the collection of the J. Paul Getty Museum, dated 1692, is an outstanding example of the estofado technique of imitating brocade in gold leaf and paint. The life-size figure retains most of its original polychromy. In previous restoration treatments, there had been an unsuccessful attempt to simulate the estofado. The present treatment included a comprehensive technical examination, using X-radiography to identify construction techniques and cross-sectional analysis for the layer structure and materials. The decoration of the sculpture was carefully studied with the goal of understanding more clearly the technique of the estofador. A cleaning strategy was then devised. Where there were losses in the estofado, it was decided to aim for a chromatic compensation using watercolours, rather than attempting to duplicate the original process.     

Durational differences in speech production under normal and delayed auditory feedback

The relationship between an individual's social perspective‐taking capacity and the complexity of that individual's dimensions for construing the behavior and character of others was examined within a general constructivist framework. A significant correlation was found supporting the hypothesis that the more differentiated the construction system of the individual the better he/she should be able to construe the perspectives of others in social situations. Evidence is also offered demonstrating the validity and reliability of the Social Perspective Task as a research instrument for examining the mode of construal of the individual.     

THE POTENTIAL OF THE CANADIAN WINTER CLIMATE FOR THE FREEZE-DRYING OF DEGRADED WATERLOGGED WOOD

Abstract

The winter climatic conditions of much of Canada provide an ideal environment for freeze-drying. We have been attempting to use these conditions for the drying of large waterlogged timbers. In the freeze-drying process the wood is kept in a frozen state and the drying proceeds by sublimation. We are particularly concerned with the treatment of large timber which present great difficulties when treated by the accepted methods. A structure was built to keep snow and rain off the wood but which allowed air to pass over it. The structure was covered with polyethylene sheet to allow the sun to shine on the wood surface and heat it. Weight changes in the wood were measured with a load transducer and temperature wa followed with thermocouple probes. Temperature and relative humidity of the surrounding air were recorded instrumentally. The timbers were of several varieties of wood in various states of decomposition. All of the wood dried quickly and much of the water was removed. This technique appears to have the potential to treat large quantities of timber in an economic and simple way.