What defines a plastic fingerprint?

A plastic fingerprint is specifically defined as a print that is left in a soft material, such as wax, clay, or putty. This type of fingerprint captures the three-dimensional details of the friction ridges of the skin, making it unique and easily identifiable. The surface of the soft material takes on the actual shape and depth of the ridges, which can provide forensic investigators with a clear and lasting impression that can be analyzed further.

The other options describe different aspects of fingerprinting but do not fit the definition of plastic fingerprints. For instance, fingerprints caught on wet surfaces tend to be categorized as latent prints, which rely on the moisture and oils from the skin. Prints left in visible substances like blood or ink are also distinct because they require different collection and examination methods. Analyzing ridge counts pertains to the classification of fingerprints generally, rather than to the physical characteristics that define plastic prints.