German States, Brunswick – 1852 2sgr, group of 17 items including four glass clichés in brown, red (dated 1927), black-brown (dated 7/31) and blue (dated 9/21) with Sperati instructional reference notations, one cliché on celluloid in black, two exposure trials in sepia-brown, accompanied with seven working essays on paper of the postmarks Braunschweig, Holzminden (comes with two celluloid clichés and ink impression on tracing paper) and Wolfenbüttel, a unique assembly. The « Ultimate » collection had just one exposure trial and no glass or celluloid clichés and, as additional reference on the rarity of clichés presented throughout this sale, the Postal Museum in Paris possesses just six clichés or matrices for all German States; nor matrices nor clichés are mentioned in B.P.A.’s Sperati I handbook.