A latent print is a chance or accidental reproduction of some area of friction ridge skin; by definition, "latent" means hidden or not visible. The pores at the tops of the friction ridges are constantly exuding water and waste products, which cover the friction ridges. When items are touched, this moisture, along with any other contaminates are deposited on the surface of the item in the pattern of the friction ridges, not unlike a rubber stamp. Since the latent print is not visible some development process must be used to make the latent print visible.