002 - Spectroscopic Analysis of "Bs"

Thanks to Dr. Richard Judge for this analysis. I asked if he would apply his analytical skills to the black Bs found on the genuine Bangkok issues as well as to those found on fakes.

Dr. Judge is an avid philatelist who has made presentations and displays. His background is in molecular electronic spectroscopy in the visible spectrum. This led to his interest in the ink chemistry of stamps especially the 2-cent red Admiral issue of Canada. Richard is a member of the Institute of Analytical Philately (IAP) and various philatelic societies.

Figure 1 – The stamps analysed

I ran reflectance and both diode 370nm and laser diode 410 on all the overprints and nothing came up as different between them. The fakes and the genuine do not fluoresce nor do they have impurities that fluoresce at a detectable level.

Figure 2 – Genuine Stamps

I had hoped to find a consistent ink in the genuine stamps that would be a fingerprint of the ink for the overprint, but this was not the case. If I am careful, I can get just the Fourier transform infrared spectroscopy (FTIR) spectrum of the ink of the overprint. The four are shown in Figure 2. I have overlapped them to try and see if the Prussian blue is in all of them. Maybe, but not conclusive, just too weak.

Figure 3 – Fake Stamps

Figure 3 is off the FTIR of the overprints of the fakes. Again, with the same caveat that I was able to get just the overprint ink and not the stamp in the plots. Fake 1 has a very large overprint and I think I was able to get it alone. Not so for the others, as I think some stamp ink is seen. Fake 4 is certainly different with the large peak at roughly 2100 cm-1 (PB). F1 and F2 may have some Prussian blue but not conclusive.

Figure 4 – Genuine Stamp with chromium

In Figure 4 the Xray is all over the place. But here are some interesting features. Genuine 1 has a cancel and I can orient the stamp so that the X-Ray Fluorescence (XRF) sees only ink, paper, gum but no cancel and no overprint (Top graph). I can orient it to get ink, paper gum and cancel. Note the large amount of chromium. I am not familiar with cancel inks. But a typical chromium compound is lead chromate which is red or dark orange. So, it adds another wrinkle to the analysis.

Figure 5 – Fake 4

Fake 4 is unique in its very strange overprint ink, see Figure 5. Note the huge iron (Fe) that confirms the FTIR peak and the weird chromium (Cr) peak.

I would very much like to hear from anyone who has something to add to what Richard has done,
see CONTACT at the top of the page.

001 - Where Revenue Stamps Overprinted "B"?

2/-	2/6	5/-

I know of three revenue stamp catalogues that list the 1874 20 cents purple and black Straits Settlements revenue, overprinted B. The earliest is by Marley (1910) followed by Forbin (1915) and finally Barefoot (2000).

I have never seen an example. The overprinting of the postage stamps “B” was a procedure to account for the fact that the Postmaster received a 10% discount on the purchase of the stamps by the Postmaster at Bangkok. The agreement with the Treasury in Singapore was only for postage no mentioned has surfaced concerning revenue stamps. The use of revenue stamps fell to the Consulate and outside of the responsibility of the Postmaster. Therefore, I must conclude that this stamp is bogus.

• Barefoot, John.: BRITISH COMMONWEALTH REVENUES, Sixth Edition ,York, U.K., J. Barefoot Ltd, 2000.
• Forbin, Alfred.: CATALOGUE DE TIMBRE FISCAUX, Paris, Yvert & Tellier, 1915
• Morley, Walter. WALTER MORLEY'S CATALOGUE OF THE REVENUE STAMPS OF THE BRITISH COLONIES INCLUDING RAILWAY STAMPS. Published 1910. 2^nd edition.