What sequence of latent print development techniques is commonly used to develop prints from porous materials?

The sequence of latent print development techniques commonly used for porous materials starts with the application of DFO (1,8-Diazafluoren-9-one), followed by Ninhydrin, and then Physical Developer.

DFO is particularly effective for developing latent prints on porous substrates because it reacts with amino acids found in the sweat residuals of fingerprints, producing a fluorescent compound. This technique is excellent for enhancing prints that might not be visible otherwise.

Ninhydrin is the next step in the sequence. When applied, it also reacts with amino acids, resulting in the formation of a purple-blue compound called Ruhemann's Purple. This process is very sensitive and can reveal latent prints that have not been visualized by the DFO treatment.

Finally, the use of Physical Developer is particularly beneficial on porous surfaces that have been previously treated with DFO or Ninhydrin but where prints are still not adequately visible. Physical Developer works well on surfaces that may have been contaminated with water or have altered their properties due to overuse of other reagents, allowing the examiner to reveal prints that may be hidden.

This specific sequence maximizes the development of prints from porous materials and is favored in forensic applications. The other choices provided mix different techniques