Which technique is often used for lifting latent prints from porous surfaces?

Ninhydrin application is a well-established technique specifically effective for developing latent prints on porous surfaces, such as paper and cardboard. This chemical reacts with amino acids and proteins found in sweat deposited by fingers, producing a purple-blue color that makes the print visible. The effectiveness of ninhydrin in revealing latent prints from porous materials lies in its ability to penetrate the surface and interact with the residues that are absorbed into the porous material.

The versatility of ninhydrin is especially valuable in forensic applications where prints may not be immediately apparent. It provides a clear visual cue, helping investigators to identify and document potential evidence.

While other methods, like superglue fuming, powder dusting, and vacuum metal deposition, serve important roles in various contexts of latent print examination, they are more effective with non-porous surfaces or have specific limitations. Superglue fuming works best on non-porous items; powder dusting may not adhere well to porous materials; and vacuum metal deposition is primarily used for non-porous surfaces as well. Therefore, ninhydrin is clearly the first choice for documents and materials that fall into the porous category.