Passive Stains
Passive stains are usually formed due to gravity. Blood drops, pools, or a flow of blood are all examples of passive stains. (NFSTC, n.d.)
Transfer Stains
Transfer stains occur when blood-covered objects come in contact with a surface. They effectively transfer blood onto it. Smears of blood, handprints, or shoeprints are all examples of transfer stains. (NFSTC, n.d.)
Projected or Impact Stains
Impact stains are bloodstain patterns caused by blood being projected through the air. Impact stains can be classified as follows (NFSTC, n.d.):
• Projection spatter: This is when blood is cast off through arterial spray, expirated spray, or cast off from an object, such as a weapon.
• Impact spatter: This is when a force or an impact occurs to a source of blood and causes it to spatter.