Lot 50611 – Spanish Colonies, Río de Oro – 1907 4p, error of colour

Spanish Colonies, Río de Oro – 1907 4p, error of colour in se-tenant pair with 3p, die proof on pelure paper in black and with dark border painted around the design, with succinct technical comments at base, including “press. 6.5” likely related to the set-up of his press and thus evidence of his printing from an engraved die; a unique and highly significant documentation.