Sublimation occurs with the use of which method?

Sublimation is the process where a solid changes directly into a gas without going through the liquid phase. Iodine fuming is a forensic technique used to develop latent fingerprints on porous surfaces, such as paper or cardboard. In this method, iodine crystals sublimate when heated, releasing iodine gas. This gas then interacts with organic residues left by fingerprints, making them visible as a brownish color.

This method is particularly effective because it allows for the visualization of fingerprints without the need for destructive chemical processes that would damage the surface. The iodine gas adheres to the oils and moisture in the fingerprints, providing a clear outline of the print.

In contrast, other methods mentioned, such as metal powdering, generally rely on particulate matter adhering to the fingerprints, rather than a direct gas transition. Chemical etching involves reacting a surface with chemicals to create a contrast, while inert gas deposition usually refers to physical vapor deposition used in different technological applications, not in the context of sublimation for forensic use.