Ninhydrin has been known to develop prints that are how many years old?

Ninhydrin is a chemical reagent used in the identification of latent fingerprints, particularly from porous surfaces such as paper or cardboard. It reacts with amino acids present in the sweat and other residues left by fingers, resulting in a colored compound that reveals the prints.

The effectiveness of ninhydrin in developing fingerprints can span several decades due to the stability of the amino acids. Studies have shown that ninhydrin can successfully develop fingerprints that are up to 50 years old. This longevity is attributed to the ability of the amino acids to persist over time, even in less than ideal conditions. Therefore, the answer indicating that ninhydrin has been known to develop prints that are up to 50 years old is accurate, reflecting the enduring nature of latent prints when properly analyzed.

Understanding the history and chemical properties of ninhydrin informs its application in forensic science, allowing examiners to recover valuable evidence from crime scenes, even from prints that may have been left decades prior.