Gunshot residue collected on pure cotton paper placed 20 cm from the barrel of a 22-caliber rifle. This residue is deposited in the vicinity of a firearm being discharged. Analysis of the direction and amount will yield how far a firearm was from a victim when the gun was discharged. The criteria most commonly used in this determination is the presence or absence of gunshot residue, the pattern diameter, and the type and distribution of gunshot residue. This image shows a field of view 6.5 cm wide.