To determine if a pattern of gunshot residues is present in the clothing, it needs to be submitted to the laboratory. Griess test is used at first because it will not interfere with the later conducted tests.
This test is used in forensics to test the traces of nitrogycerine. Nitrite residues indicate a presence of smokeless gunpowder. Presence of nitrites is indicated if the solution in the test turns pink. However, to see if the test is positive it is also needed to add Griess regent to another bowl and the solution needs to remain clear.
This test is used by firearms examiners to determine a muzzle-to-garment distance.
