Latent Fingerprint evidence is the most common type of fingerprint evidence found at a crime scene. Latent prints are the result of perspiration transferred to some object. Many times prior to restoration, the prints are invisible to the human eye.
Persperation or sweat is composed of:
98.5% to 99.5% water
and
00.5% to 01.5% solids
These solids are composed of oil, amino acid, and salt.