Raman Spectral Comparator.

We have two Raman Spectral Comparators in the University Science building. One is a basic model used mainly for the examination of inks & dyes in Document Evidence practicals and is also used by final year project students. The other is a larger and highly sophisticated dual laser version used for research purposes by our PhD students. This instruments main purpose in Forensics is to compare ink samples. This is especially important in the recognition of highly sophisticated banknote and document forgeries where identification of the ink used to make the forgery can provide valuable glues as to their origin.  Each type of ink or dye will have a particular spectral characteristic. Provided we have a sample ink to match the ink we are testing, or a spectral graph to compare it to, we can then determine whether we have a match for the ink or not. The Bank of England has a full database of the inks they use on all there banknotes. Understandably they are reluctant to let anyone else have it! The technique used is known as Raman Scattering, which in short produces a Spectral graph with characteristic peaks and troughs.

Back to Equipment List