Comparison of genuine (1851–1852 <scp>AD</scp>) and forged or reproduction Hawaiian Missionary stamps using Raman microscopy

Abstract

Abstract The rare and valuable Hawaiian Missionary stamps from the Tapling Collection held at the British Library were analysed using Raman microscopy and shown to be printed with an ink composed of Prussian blue. Blue particles dispersed between the paper fibres of the stamps and present as optical brighteners were identified to be lazurite or the synthetic equivalent, ultramarine blue. Each cancellation or postmark, where present, is composed of carbon, vermilion, iron(III) oxide or a madder‐like organic pigment. The Raman analysis also showed that microscopic repair work on stamps can be identified. The genuine stamps were compared with 13 forged Hawaiian Missionary stamps, printed in the early 20th century, and with a set of eight reproduction items printed in 1985, from the Royal Philatelic Society London. Raman analysis of the forged stamps showed that the ink used is different from that of the genuine stamps, being a mixture of Prussian blue and ultramarine blue, or an organic blue pigment. Analysis of the 1985 reproduction stamps showed that they were printed with modern phthalocyanine blue ink, on paper coated with a yellow organic pigment to simulate aged paper. This analysis provides an invaluable and non‐destructive method for assisting in drawing a distinction between fraudulent or reproduction material and the genuine article. Copyright © 2002 John Wiley &amp; Sons, Ltd.