Why would a forensic examiner choose to use Ninhydrin over other reagents?

A forensic examiner would choose to use Ninhydrin over other reagents primarily because it is effective in developing latent prints on porous materials. Ninhydrin reacts with amino acids present in sweat, which is left behind when a person touches a surface, particularly on porous items like paper, cardboard, or fabric. This reaction results in a color change that reveals the fingerprints, making them visible for examination.

The specificity of Ninhydrin for porous surfaces is crucial in forensic investigations, as many latent prints are found on these types of materials. Other reagents might not be effective or suitable for such surfaces, limiting their utility in certain scenarios. Thus, the ability of Ninhydrin to develop prints in challenging contexts, such as on paper, makes it a preferred choice for forensic examiners when working with porous substrates.