Chromatography can be used by historians, in order to discover clues about the past, from the written evidence that remains to this day.
Chromatography is a scientific process which is used to separate mixtures such as ink, paint, dyes... Into the individual compounds that make them up.
In terms of studying history, this can be useful because isolating and studying ink in this way allows historians to take a very old document, signature or letter, and trace where and when it came from.
In the past, certain types of ink could only be found in very specific parts of the world.
Also, throughout the ages, they way inks and dyes have been produced has changed greatly. So, through the use of chromatography, an historian would easily be able to tell whether a dot of ink on a paper came from the period of the American Revolution, or the French Revolution.
