- The uniqueness of fingerprints combined with the ease with which they are left on a surface when touched makes them an invaluable aid to those seeking to solve crimes.
- Fingerprints are relatively easy to find at crime scenes and latent prints may be visualised using a logical sequence of tests, some chemical and some physical.
- The chemical tests include oxidation and reduction reactions, called redox reactions, and acid-base reactions.
- The physical methods for visualising latent fingerprints include fluorescence of contaminants induced by illumination with high intensity light or lasers, and the application of powders that adhere to grease or dirt present on the print.
- In general, fingerprint use in identification is very reliable, although every attempt must be made to remove or minimise errors.
- There are various databases of fingerprints. In England, Scotland and Wales the new system IDENT1 was introduced in 2007.