What is believed to be the world's oldest fingerprint bureau is celebrating its centenary in Calcutta, India.
The method of identification was developed by a Bengali police chief in 1897, and has since been adopted by police throughout the world to track down criminals.
The Fingerprint Bureau in Calcutta celebrates its 100th anniversary.
The bureau believes it is the oldest of its kind in the world.
And the technique of identifying someone by their fingerprints is also celebrating its centenary.
The method of indexing and classifying fingerprints was developed in Calcutta in 1897 by the then police chief of south Bengal, Sir Edward Richard Henry.
Soon after, the Writers' Buildings in the city became what is believed to be the first fingerprint bureau in the world.
Since then, the fingerprinting technique has been adopted by police across the globe as a method of identifying criminals.
A former Director General of Police in India said fingerprints have been invaluable in identifying and convicting criminals.
"This system of identification through fingerprints is very helpful for the purpose of identification of criminals, and proving their participation in crime before the court."
SUPER CAPTION: Satyabrata Basu, retired Director General of Police
The bureau includes a museum which charts the history of fingerprinting.
The museum is also home to Sir Henry's first book on the classification and uses of fingerprints.
Although Sir Henry's method of indexing and classifying fingerprints is still in use, sophisticated equipment is now used to record fingerprints in the bureau's laboratory.
Micro photocopying is used to give an extremely accurate record of fingerprints, while chemicals can also be used to highlight prints.
A fingerprint expert at the bureau said it was now possible to detect seemingly invisible prints.
"The best method is the imaging process. In this process, prints which are not visible ordinarily on papers, particularly on currency notes, or like this, may be visible after treatment of the imaging process."
SUPER CAPTION: Prasanta Saha, Fingerprint expert
Modern technology means experts can now read smudged fingerprints, which is proving invaluable in solving crimes in which there are few other clues.
The Director of Police Records in West Bengal explained just how important a role the method of identification plays in solving crimes all over the world.
"Fingerprint has its applicability universally, both for civil and criminal crime related purposes, it can play a very effective role."
SUPER CAPTION: S.K. Ghosh, Director of Police Records, West Bengal
But although the ways of finding and recording fingerprints may have come a long way since Sir Henry's time, his century-old method of indexing and classifying them is still with us today.