The newly discovered 1937 Burma 4As George V error of colour.

Is this the British Commonwealth's equivalent of the Tre Skilling Banco of Sweden?

1937 India multiple star 4as sage-green overprinted BURMA/SERVICE, cancelled with RANGOON cds. which falls over the overprint. The normal 4As sage green stamp.	1937 India multiple star 4as pale orange overprinted BURMA/SERVICE, cancelled with the MOULMEIN cds. which falls over the overprint. The error of colour, printed in the colour of the 2As6p value.

Sweden The 1855 Tre Skilling green. The normal stamp.	Sweden The unique 1855 Tre Skilling 'yellow'. The error of colour, printed in the colour of the 8 skilling value.

Introduction

How can we be certain that in some cases a colour difference between two contentious stamps is actually the result of a genuine printing using two different printing inks, or a faked variety obtained through manipulation using chemicals, or a discolouration obtained through exposure to various forms of light or air? 

There is absolutely no doubt however that analytical science is the only route by which we could be certain. While we can make informed decisions which may well be absolutely right, or at times completely wrong, we can never be 'certain' in the case of a major colour error. This is because opinions, which are generally based on experience and the use of comparators and light magnification, are subjective and rely on the ability of the individual to reach an opinion based on observation and experience, there are no traditional ways of analysing the ink constituents. 

External agents such as bleaches, solvents, chemicals, light and air which can alter the colour of a stamp mainly through a process of oxidation will not alter the integrity of the main elemental constituents of the ink used to print it. 

When expressing an opinion of genuineness on an error of colour using the standard equipment available to us, we can never be certain that the inks used to print the normal stamp and the colour error are different. Similarly, when expressing a correct 'faked' opinion on a faked colour changeling, we can also never be certain using the basic equipment available to us, that the ink that printed the normal and the changeling are the same. A genuine colour error would be printed from a different ink to the normal stamp while a faked or colour changeling would be printed using the same ink. 

Science however, in the case of a colour difference is 'King'. It can tell us, in no uncertain terms, what the inorganic elements that constitute the printing ink are. Furthermore science is not subjective and will produce repeatable results. This fact can therefore give us the confidence when expressing an opinion as far as printing ink is concerned. 

There are two forms of scientific analysis that are available to us today that would identify the elements present in a printing ink. These are Raman spectroscopy and X-ray micro fluorescence (EDXRF). Both will analyse the constituents of the printing ink down to elemental levels, and while both analytical instruments will give us a full report of the elements present in an ink used to print a stamp, Raman spectroscopy will also give us an indication of the compounds from which these elements originate. Both instruments will also show up any other inorganic contaminants and trace elements, if they exist. 

Using this highly specialised equipment we are now in a position to be certain that if two stamps show differing main elements in the ink that printed them, then we can quite safely conclude that two different inks have been used. 

An examination

A classic case in question is the incredible and newly discovered 1937 Burma GV 4As value overprinted on an India GV multiple star watermark with the words 'BURMA/SERVICE' illustrated above.

The 4As value in question, which should be sage green in colour, is printed in the orange colour of the 2As6p value forming an undoubted major 'error of colour'. This error is very much akin to the Tre Skilling Banco error of Sweden. 

How can we be certain that the 4As value in orange is in fact a genuine error of colour printed from a different ink or a faked stamp or colour changeling of a 4As sage green stamp?  Whether right or wrong we can never be certain. Science, however can be.

Both the 4As sage green (normal) and the 4As orange (the error of colour) were examined by the Reading Scientific Laboratories using X-Ray micro fluorescence. An example of the 2As6p orange was also sent for examination. Below are images of the stamps including the error of colour and the EDXRF readings which conclusively prove that the stamp showing an error of colour is printed from a different ink. 

The readings from the2As6p orange are of great interest as they have been found to be very similar indeed to those of the 4As orange error of colour, very much endorsing the fact that the ink used to print the 2As6p value was also used in error to print the 4As value. This similarity eliminates any opinion of faking as it is only with this very modern equipment that we can analyse the constituents of printing inks. There is no way that a forger is able to constitute an ink as identical as this both qualitatively or quantitatively without information from such modern equipment. 

The EDXRF trace for both the normal 4As sage green and the 4As orange 'error of colour' as well as that for a normal 2As6p orange

EDXRF trace for both the 4As sage green (normal colour- blue trace) and the 4As pale orange (error of colour- red trace) Note the the presence of lead and absence of iron, zinc and barium in the error of colour.	EDXRF trace for the 2As6p orange (normal colour- red trace) and the 4As orange (error of colour- blue trace) Note the similarity between them and the important presence of lead in both.

Conclusions

It is abundantly clear from the readings above that both stamps have a different ink make up from each other.

The 4As sage green shows iron, zinc, barium and chromium as the main colour constituents in the printing ink, while the 4As pale orange error of colour and the 2As6p normal colour both show mainly lead in the printing ink.

The 4As sage green: The elements present indicate that the following pigments may have been used- Raman testing would very probably indicate the compounds.

Iron oxide- a pigment found in various colours and forms, Barium chromate- a yellow pigment or perhaps barium sulphate, a white pigment. All three compounds are known pigments and used as such.

The 4As orange error of colour and the 2As6p orange: The elements present indicate that the following pigment may have been used: Raman testing would very probably indicate the compounds.

Lead oxide Pb3O4 (red lead). A known pigment and used as such.

The above data can but form conclusive proof that the 4as pale orange stamp is not colour 'changeling' but a stamp printed from a different ink.

Further reading on how science was used to authenticate a great world class rarity

Raman and EDXRF have played an invaluable role in the authentication of an incredible GB cover franked with three examples of the iconic 1864 1d rose red stamp with a plate number 77. 

http://1dplate77.com/1dplate77/IsthisthephilatelicJusticeaworldclassphilatelicgemdeserves.htm

X ray microfluorescence in printing ink analysis

Elemental analysis of postage stamp printing inks