THE CONSERVATION OF PYRITIC STONE ANTIQUITIES

Abstract

The occurrence and identification of ‘fossil disease’ in stone artifacts is described, together with details of techniques for the stabilization and consolidation of the specimens.     

NOTE ON THE TECHNIQUE AND CONSERVATION OF SOME THANG-KA PAINTINGS

Abstract

The article is a concise report on the art historical as well as technical aspects of thang-ka paintings. It also describes briefly the traditional methods and materials employed in the execution of these paintings. The artists’ materials described in the literature are compared with actual findings as a result of analysis of pigments, binding media and other materials involved in the execution of the thang-ka paintings. An outline of the causes of deterioration of thang-kas is also mentioned. Finally, an extensive account is given of the method of treatment carried out in the author's laboratory.     

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 AND TECHNIQUE OF SILVER BANGLES DISCOVERED AT ROJDI,INDIA

Abstract

The treatment of two silver bangles found at Rojdi and dated c. 2000 b.c. is described. The bangles were separated by removing the hard incrustations with a 20% sodium hexametaphosphate solution and 15% acetic acid. Silver chloride was removed with a 25% solution of 0.88 ammonia and a 20% aqueous solution of ammonium thiosulphate.

Silver sulphide was removed in a 20% formic acid bath. Polyvinyl acetate was used for consolidation, and a coating of polymethyl methacrylate was applied. The silver was found to contain copper and lead. The causes of embrittlement and the manufacturing technique are discussed.     

THE CONSERVATION AND TECHNIQUE OF THE HERLIN ALTARPIECE (1466)

Abstract

The restoration of the Hedin altar in Rothenburg o.d.T., dated 1466, is described. The polychromed sculptures were cleaned and loose paint was fixed. Methods and materials used in the restoration of the paintings, the areas polychromed in various techniques and the brocade reliefs are mentioned. The altar was protected from direct sunlight. The construction of the shrine and the technique of carving are extensively discussed. Sculptures made from one piece of lime wood were hollowed out and closed with a plank. Traces of rough finishing are visible. Shrine and predella were polychromed after a preliminary assembly of the sculptures. The various techniques used in the undisfigured polychromy are described as they are observed with the unaided eye. It can be shown that the working methods were rational. The fabrication of relief brocades and the various patterns used are discussed in detail. The treatment of the various paintings on the wings, the predella and the reverse of the shrine is reported. The question is raised to what extent the painter Herlin can also have been responsible for the polychromy.     

THE DISCOVERY AND CONSERVATION OF AN ANCIENT EGYPTIAN LINEN TUNIC

Abstract

The archaeological evidence for dating a linen tunic found amongst other pieces from the Petrie Museum of Egyptian Archaeology, UCL, is weighed against the evidence from Carbon-14 dating. An account of the structure, conservation and mounting of the tunic is then given.     

THE CONSERVATION OF NON-METALLIC SEALS

Abstract

The conservation of non-metallic seals is an aspect of archival conservation which is all too often neglected.The authors show the most usual causes and forms of damage together with various methods of treatment. Among the aspects discussed are composition and manufacture; cleaning and repair of single and double-faced seals made of beeswax, shellac and other thermoplastic compounds; the conservation and repair of papered seals, together with seals and wafers applied en placard to documents; and methods of packing and storage used in the University of Glasgow Archives.     

CORROSION AND CONSERVATION OF A SILVER VISCERAL VESSEL FROM THE BEGINNING OF THE SEVENTEENTH CENTURY

Abstract

Two different cleaning methods were found necessary to remove silver chloride corrosion products from different areas of a silver canopic vessel containing about 6% of copper. Two possible mechanisms of silver corrosion which could have led to the differing silver chloride corrosion products are put forward.     

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.     

THE RESTORATION AND CONSERVATION PROJECT OF BOROBUDUR TEMPLE,INDONESIA PLANNING - RESEARCH - DESIGN

Abstract

A survey is given of the environment of the monument, including its geographical and geological setting and meteorological data collected near the monument. The construction of Borobudur and the origin and consequences of damaging factors such as uneven settlements are discussed. Preliminary research required e.g. drilling programmes, soil mechanical studies, stone deterioration studies and investigations into the manufacture of concrete for foundations from local sources. The technical solutions proposed for the safeguarding programme are described in detail. Cost estimates, the organisation of the restoration project and landscaping and site development are mentioned. The duration of the project is estimated at six years. The complex and multi-disciplinary nature of the project requiring systematic planning both in the research and preparatory phases and in the implementation is stressed. Disciplines involved include amongst others: airphoto analysis, archaeology, architecture, chemistry, conservation techniques, geology, geophysics, hydrology, impermeabilization technology, landscape planning, microbiology, petrography, physics, soil mechanics, surveying and terrestrial photogrammetry.     

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.     

THE RESTORATION OF TWO MARBLE STATUES BY ANTONIO CORRADINI

Abstract

The restoration of two early eighteenth-century marble statues by Antonio Corradini is described. Methylene chloride was used to remove plant stains. Sepiolite (magnesium silicate) and water drew out the dirt, and thick incrustations were removed with an ultrasonic dental tool. Incorrectly restored parts were remodelled according to contemporary prints, not in marble but using a casting procedure.     

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.     

INVESTIGATIONS OF WEATHERING CRUSTS ON SALZBURG STONE MONUMENTS

Abstract

A series of corroded stone specimens from Salzburg monuments was examined by electron-probe microanalysis. The crusts arose from environmental effects, in the case of marble primarily from SO₂. Deterioration phenomena can be correlated with stone surface features.