IAI Latent Print Certification Practice Test 2025 – Complete Exam Prep

The key reaction that Ninhydrin undergoes in the development of latent fingerprints is its ability to combine with amino acids. When Ninhydrin is applied to a surface containing latent fingerprints, it reacts specifically with the amino acids that are present in the perspiration left behind by the fingers. This reaction results in the formation of a colored compound, which is typically purple or blue, allowing the fingerprints to be visualized.

The significance of this reaction lies in the fact that most latent fingerprints are not just composed of oils and dirt; they contain a variety of substances, including amino acids, which are byproducts of the body's metabolic processes. By targeting these amino acids, Ninhydrin serves as a useful chemical in forensic investigations, as it enhances the visibility of fingerprints that might otherwise be too faint to be detected.

Other reactions or properties mentioned in the other choices do not directly relate to how Ninhydrin functions in developing latent prints. For instance, while lipids and moisture are parts of the fingerprint composition, their reactions do not provide the specific visual outcome associated with Ninhydrin. Instead, Ninhydrin’s unique interaction with amino acids is what makes it an essential tool in forensic science for fingerprinting.