Passive stains
Examples: pools, flows, drops
These stains are usually from gravity acting on an injured body or source of blood.
Transfer stains:
Examples: boot prints, hand prints, wipes
These stains are a result of a bloody object transferring blood onto a surface or object.
Impact stains:
Examples: spatter, splashes, gushes
These stains usually occur when an object or person hits a static pool of blood.