What type of fingerprints are classified as invisible to the naked eye?

Latent fingerprints are classified as invisible to the naked eye due to their composition—primarily made up of natural oils and sweat from the skin. These fingerprints are not easily seen on surfaces without the use of special techniques or chemicals that can reveal them, making them distinct from other types of fingerprints.

Patent fingerprints are those that are visible because they have been transferred onto a surface in a manner that makes them apparent, such as through ink or blood. Plastic fingerprints are three-dimensional impressions left in materials like wax or clay, which also make them visible. Visible fingerprints, as a category, are any prints that can be directly seen.

Understanding this classification is essential for forensic investigations, as discovering and documenting latent fingerprints often requires specific methods such as powdering or chemical fuming to make them visible for analysis and comparison.