Reportedly Trivulzio collection, Milan; (Count Alessandro Contini-Bonacossi, Florence); purchased by 1937 or 1939 by Samuel H. Kress, New York, as Venetian, c. 1400; gift 27 February 1950 to the Samuel H. Kress Foundation, New York; gift 1961 to NGA.
- Distelberger, Rudolf, Alison Luchs, Philippe Verdier, and Timonthy H. Wilson. Western Decorative Arts, Part I: Medieval, Renaissance, and Historicizing Styles including Metalwork, Enamels, and Ceramics. The Collections of the National Gallery of Art Systematic Catalogue. Washington, 1993: 71-76, fig. 72.
The blue enamel on the frame has suffered some damage, with losses on the lower proper left. The construction, with long pins passing through tubular hinges on the interior to hold the front and back together, corresponds in general to that of at least one known fifteenth-century goldsmith work, the Holy Thorn reliquary at the British Museum, London. Tiny holes at regular intervals around the interior of the central opening suggest that pins or nails were once inserted to secure something there. A tiny copper wire passes through one. The interior of the frame is lined with worn red cloth of indeterminate age.
The pigments in the miniature are unusually coarsely ground for the 1480-1500 period suggested by the style. The very smooth support appears to be parchment that has been glued onto cardboard.
X-ray fluorescence spectroscopy indicated that the surface of the metal pax frame is silver and gold, with traces of copper; that the back is fire-gilded brass riveted onto copper; and that the plinth and handle are silver with traces of copper and lead. One of the long interior pins holding the front and back together is brass and the other is iron. The blue and gold enameled areas contain silver, gold, copper, iron, and possibly zinc, while the green enamel on one knob contains silver, copper, gold, lead, and traces of iron. No demonstrably modern colorants are present in either the enamel or the miniature. X-ray fluorescence of the latter, and X-ray diffraction analysis of minute samples, indicated the presence of lead-tin yellow, not normally found after 1750, in Joseph's cloak; and malachite, replaced in Europe by artificial green pigments c. 1800, in the greens. Traces of arsenic in a green area may indicate the presence of the yellow pigment orpiment, known since classical times. A blue area contains smalt, found (infrequently) in paintings from c. 1500-1800, and rarely thereafter. Minute traces of zinc in a gold halo, a light green area, and a gray wall could indicate the use of zinc white (introduced only in 1834) or simply impurities.
 Hugh Tait, Catalogue of the Waddesdon Bequest in the British Museum. I. The Jewels (London, 1986), 32, fig. 12-14, 34, with photographs in a dismantled state.
 Verbal report of Shelley Fletcher, NGA paper conservator, 2 April 1985; reaffirmed following microscopic examination of a sample, 9 June 1992.
 Report of 10 May 1985, in NGA conservation laboratory files.
 Reports of 10 May 1985 and 29 October 1985, in NGA conservation laboratory files; discussion with the author after further examination by Barbara Berrie, 12 January 1989; and report of Suzanne Q. Lomax, 13 January 1989. The dates are discussed in Hermann Kuhn, "Terminal Dates for Paintings Derived from Pigment Analysis," in Application of Science in Examination of Works of Art, ed. William J. Young (Proceedings of the Seminar June 15-19, 1970, Museum of Fine Arts, Boston, Mass.), 199-205. On smalt, whose production has continued up to the present, see Bruno Mühlethaler and Jean Thissen, "Smalt," Studies in Conservation 14 (1969), 47-61. I owe these references to Barbara Berrie.