Chemical development of latent fingerprints: 1,2-indanedione has come of age

The performance of 1,2-indanedione as a latent fingerprint reagent on some types of paper was found to exceed that of DFO, the leading fluorogenic fin gerprint reagent. It even exceeds the performance of the sequence, DFO, fol lowed by ninhydrin. No new prints could be observed when ninhydrin was appl ied after indanedione. On a large number of actual exhibits (used checks) i ndanedione developed 46% more identifiable prints than the sequence DFO-nin hydrin. A standard procedure for fingerprint development by indanedione is proposed . Best results are obtained with a 0.2% indanedione solution in HFE7100 sol vent containing 7% ethyl acetate, but no acetic acid. It can be recommended to start using 1,2-indanedione, which is already commercially available, i n actual fingerprint casework.