Lorne Campbell, Jill Dunkerton, Jo Kirby and Lisa Monnas
Technical Bulletin Volume 22, 2001
The weave structure found in 15th-century Italian silk velvets is compared with the purple velvet on the reverse of a diptych attributed to Ercole de' Roberti.
Quantitative dye analysis by high perfromance liquid chromatography (HPLC) was carried out to identify Polish cochineal (as distinct from Mexican cochineal, whose presence would have given an earliest date of production of the diptych). Madder in orange fibres and indigo on deep purple threads were also identified.
Dye mixtures used to make purple, contemporary literature on dyeing, contemporary marking of the dye used in the selvedge, and 15th-century Italian terms for purple are discussed. Wear on the velvet makes it clear where fastenings were placed: the diptych opened like a book.
This technical study shows it is likely that the diptych belonged to a particular owner, since it was shown to match a description in a contemporary inventory very closely. Details of the weave analysis and the HPLC conditions are given in an appendix.
dye, Ercole de' Roberti, panel paintings, primary source documents, purple, velvet
To cite this article we suggest using
Campbell, L., Dunkerton, J., Kirby, J., Monnas, L. 'Two Panels by Ercole de' Roberti and the Identification of "Veluto Morello"'. National Gallery Technical Bulletin Vol 22, pp 29–41.
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