Replica diptych, signs of the zodiac, Byzantine 800-900 CE, fictile ivory plaster cast, made by Elkington & Co, London, England, 1855-1887
Many of the casts were taken from the original artworks by J. O. Westwood and A. Nesbitt. At first they used gutta-percha alone, but it was found that after being softened in hot water it hardened again too rapidly to allow a large ivory to be properly pressed. Hence they mixed wax with the gutta-percha, which caused it to retain its softness for a longer period. The prepared gutta-percha was then to be placed in hot water (which was not allowed to boil), and when it became as soft as putty it was moulded by hand into a flattened plate rather larger than the artwork to be moulded. The face of the artwork was wetted with clear cold water, or washed over with soft soap and while wet the gutta-percha was placed upon it and pressed by the thumb carefully so as to force the gutta-percha into all the deeper cut parts of the artwork.
It was then allowed to harden and cool, after which it was lifted with great care from the artwork. Once removed the mould was ready to receive the fluid plaster of Paris of the finest quality. Westwood notes that when a number of copies were required an electrotype made of the mould was preferred to ensure every cast was as fresh as the first. In this manner a considerable number, both of moulds and electrotype moulds, were accumulated by Alexander Nesbitt, A. W. Franks, and J. O. Westwood. These were later transferred to the Arundel Society, who sold copies of the casts from 1855.
The beauty of the casts made from these moulds was universally acknowledged at the time as they were made with the finest plaster of Paris by Messrs. Franchi, whose business was transferred to Messrs. Elkington, who continued to sell nearly all of the specimens taken by Nesbitt and Westwood. When properly made, and carefully coloured by hand from the originals, (the surface allowing the application of common water colours), it was next to impossible to distinguish one of these casts from the original.
Walrus ivory ceased to be used in Europe long before the nineteenth century and most examples date back to medieval and Carlovingian periods. In addition the scarcity of Elephants in the medieval period limited its use, although it is important to note that frozen fossil tusks from mammoths had been used, particularly in Russia. Among ivories there is a wide difference in the condition and colour. This is not caused by the origin of the material, or even necessarily the age, as some newer pieces are among the most discoloured and brittle in appearance. It seems the innumerable possible accidents to which carved ivories are exposed from age to age accounts for this great difference.
Westwood, J. O., A Descriptive Catalogue of the Fictile Ivories in the South Kensington Museum, printed by George E. Eyre and William Spottiswoode, printers to the Queen's Most Excellent Majesty, Piccadilly, London, 1876
Between 1884 and 1887 the Museum of Applied Arts and Sciences acquired over 650 plaster cast reproductions of European Medieval carved artworks into its collection. These were purchased from: F. Kusthardt in 1884; J. Kreittmayr in 1885; and Messrs Elkington & Co between 1885 and 1887.