Which reagent is commonly associated with developing fingerprints on porous materials?

Ninhydrin is a commonly used reagent for developing fingerprints on porous materials because it reacts with amino acids present in sweat, which are often left behind in the residues of latent fingerprints. Upon application, ninhydrin undergoes a chemical reaction that produces a colored complex, typically a blue or purple hue, thereby making the latent prints visible.

This method is particularly effective on porous surfaces such as paper, cardboard, and untreated wood, where fingerprints can become embedded within the fibers, making them less accessible for traditional developmental techniques. Ninhydrin has been a longstanding choice in forensic science for its reliability and effectiveness in revealing latent fingerprints.