Mauritius, “Post Paid” - 1848 1 Penny, glass support cliché with image reversed in orange-red, with notation at top right in Sperati's hand; around twelve glass clichés recorded of this iconic issue, being inexistent in the Postal Museum of Paris and with only one cliché in the B.P.A. (Image)

Mauritius, “Post Paid” - 1848 1 Penny, glass support cliché with reversed image in grey black; around twelve glass clichés recorded of this iconic issue, being inexistent in the Postal Museum of Paris and with only one cliché in the B.P.A. (Image)

Mauritius, “Post Paid” - 1848 1 Penny, cliché on celluloid in black and with image reversed, marked in Sperati’s hand “31/12” and “C.14”; this is a characteristic Sperati reproduction of the “Post Paid” issue, reproduced from a worn impression original stamp, pos. 10 in the sheet. (Image)

Mauritius, “Post Paid” - 1848 1 Penny, essay on white wove paper, comprising two impressions in an orange-red shade, with notations made by Sperati; a very rare experiment on paper. (Image)

Mauritius - 1879 38c, glass master negative in black, broken and affixed on a smaller glass by Sperati; an exceptional item with no other cliché or trial exposure in the “Ultimate” Collection. The matrix is the most important and first element in the process of reproduction, and this is unique. (Image)

Mauritius - 1879 39c, glass support cliché in brown, a horizontal pair printed as tête-bêche. (Image)

Mauritius - 1879 38c, trial exposure on glass in light brown, showing a vertical crack through the glass stemming from the master negative; a unique item with no other cliché or trial exposure in the “Ultimate” Collection. (Image)

Mauritius - 1879 38c, trial exposure on glass, somewhat damaged by humidity, in a light brown shade; an extremely rare trial with no other cliché or trial exposure found in the “Ultimate” collection. (Image)