Papua 1907 2d black and violet. SG40aPapua 1907 2d black and violet, thin paper watermark vertical, type 4 'Papua' overprint of Brisbane, ERROR OVERPRINT DOUBLE, SG40a. An exceptional unmounted mint example with full original gum. Tiny trace of gum toning mentioned for accuracy, but very fine appearance. Position 13 from the one sheet of 30 that existed, which remained unknown to the wider philatelic world until 2003 (first listed in British Commonwealth & Empire catalogue, Part 1 in