A different approach to this issue has been tested for the present
paper. Precisely, we explored the possibility to investigate the
forensic evidences in the NIR spectral region (i.e. 700–1000 nm).
Although the NIR region has been explored in several studies [12,13],
to the best of our knowledge it was never applied to the thermal
paper. A related technique, the Fourier Transform Infrared chemical
imaging [14], was investigated in order to solve background
interference problems but without remarkable results. Even the
present study is based on the investigation of evidences in the NIR
region and it allows to detect hidden fingermarks even in presence of
the usual dark stain over the latent fingerprint that appears when the
thermal paper is treated with amino acids sensitive reagents. The
suggested method is not invasive since it exploits the different
behavior of the paper with respect to the treated prints when
observed in the NIR. This difference allows to inspect forensic
evidences usually discarded after the treatment.[9]; the use of washing solutions to remove the active coat