Ninhydrin has been known to develop what age of old prints?

Ninhydrin is a chemical reagent commonly used in forensic science for developing latent fingerprints on porous surfaces. It reacts with amino acids present in sweat and other residues left behind by fingertips. The significant feature of ninhydrin is its ability to develop older prints, specifically those that may be several years old.

The correct choice, indicating that ninhydrin can effectively develop prints that are approximately 30-35 years old, reflects its longevity and efficacy in fingerprint analysis. Over time, the residues left by fingerprints can degrade, but ninhydrin remains capable of reacting with certain components of those residues even after many years have passed. This ability to develop older prints is particularly valuable in forensic investigations where the age of the print could play a critical role in determining its relevance to a case.

In contrast, the other options indicate shorter time frames that do not fully capture the utility of ninhydrin in developing aged prints. While ninhydrin may also be effective for younger prints, it is the extended range of 30-35 years that showcases its practical application in cases involving older latent prints.