What is a characteristic of latent fingerprints?

Latent fingerprints are primarily characterized by their invisibility to the naked eye. They are formed by the natural oils and sweat from an individual's skin being deposited onto a surface. These impressions are often not immediately apparent, which is why they can only be detected under specific conditions, such as using physical or chemical methods to reveal them.

The requirement for specific detection conditions emphasizes the unique nature of latent fingerprints—they often need enhancements to become visible for forensic analysis, rather than being immediately perceivable. This characteristic is essential for fire investigators and law enforcement, as it indicates the need for careful processing of a crime scene to ensure that valuable evidence is not overlooked.

In contrast, options suggesting that latent fingerprints are always visible or require a special light to be detected misrepresent their inherent characteristics, as latent prints typically rely on techniques beyond mere visual observation for detection. The assertion that they are never preserved properly does not align with established forensic best practices, which often include meticulous preservation methods.