What technique involves using heat to reveal latent fingerprints on nonporous surfaces?

The technique that involves using heat to reveal latent fingerprints on nonporous surfaces is fuming. This process typically utilizes chemical vapors, such as those from superglue (cyanoacrylate), which can be heated to produce fumes. When these fumes come into contact with the moisture and oils in the latent fingerprints, they adhere to the residues, resulting in a visible imprint that can be photographed or lifted for analysis.

Fuming is particularly effective on nonporous surfaces like glass, plastic, and metal since these materials do not absorb the fingerprint residues, allowing the chemical vapors to interact more directly with the prints. This method is widely used in forensic science because it can reveal fingerprints that are otherwise invisible to the naked eye, assisting law enforcement in investigations.

In contrast, sublimation refers to a process where a solid turns directly into a gas without going through a liquid phase, typically not applicable when discussing heat treatments for revealing fingerprints. Acid treatment usually involves the use of acidic solutions to enhance prints, which is more effective on porous substrates. Thermal imaging is a technique that uses infrared to visualize heat patterns but does not specifically pertain to revealing fingerprints.