Soot (Blackening)
Definition
Submicrometre carbon-rich particles from incomplete propellant combustion, deposited on the garment or skin surface around the entry hole at contact and near-contact range. Visible as dark discolouration. Easily removed by friction or handling.
- Composition
- Submicrometre carbon-rich particles from incomplete propellant combustion
- Range limit
- Roughly under 15 cm for most handguns
- Removability
- Wipes off with a damp swab or friction
Common questions
What is soot blackening in a gunshot wound?+
Soot blackening is a dark deposit of fine carbon particles that forms around a bullet entry wound. It comes from incomplete combustion of propellant gases during firing. The soot wipes off easily with a damp cloth or through handling.
How far away can soot blackening appear from a shot?+
Soot blackening forms at contact and close range, roughly under 15 cm for most handguns. The carbon particles lose momentum quickly in air, so the effect is limited to distances where unburned propellant gases still reach the target.
Why is soot blackening easy to remove?+
Soot particles are loosely deposited on the surface. Any friction or handling, including a simple damp swab, can wipe them away. This distinguishes soot blackening from other range indicators like powder tattooing, which embeds particles into skin and fabric more permanently.
Related terms
- Modified Griess Test
- A contact-transfer colour chemistry test for nitrite-containing propellant combustion residue. Sulphanilic acid undergoes diazotisation with nitrous acid (from NO2 on the target...
- Powder Tattooing
- Stippling pattern of unburned and partially burned propellant grains embedded in the skin around an entry wound. Cannot be wiped off. Pathognomonic...
- Azo Dye
- A class of organic dyes containing one or more azo groups (R-N=N-R'). Formed in the Griess test by coupling of a diazonium...
- Bullet Wipe
- Greyish to brownish ring of lubricant, lead and copper rubbed off the bullet onto the margin of an entry hole in clothing....
- Contact Shot
- Muzzle pressed against skin or clothing at the moment of firing. Hallmarks are a stellate (star-shaped) wound from sub-dermal gas tracking, a...
- Desensitisation (Griess Protocol)
- The step in the Modified Griess protocol in which background nitrite contamination (from sweat, atmospheric nitrogen, detergent) is removed from the garment...
- Lead-Free Primer
- A primer composition that omits lead styphnate, using DDNP or other compounds, producing no lead from the primer channel during discharge. Examples...
- Range of Firing
- The distance from the muzzle of the firearm to the target at the moment of discharge. Estimated from wound geometry, soot pattern,...
- Sodium Rhodizonate
- A chelating agent producing a scarlet-to-red colour with lead ions at acid pH. Applied to entry-wound margins and garment entry holes to...
- Sodium Rhodizonate Test
- Colour test for lead. The cloth is treated with sodium rhodizonate followed by buffer; lead deposits give a pink-to-red colour, confirmed with...
- Stippling
- Abrasion marks on skin or fabric produced by partially burned propellant grains exiting the muzzle with sufficient velocity to mechanically impact the...
- Test-Fired Control Panels
- Fabric panels fired at known, measured muzzle-to-target distances using the same or equivalent weapon and ammunition as in the case, processed with...
Explained in these topics
- Determination of Range of Firing in Firearm CasesLoose carbonaceous deposit around the entry wound from combustion gases. Wipes off with a damp swab. Limited to close range (roughly under 15 cm for most handg...
- Powder Tattooing, Stippling, Blackening and the Modified Griess TestSubmicrometre carbon-rich particles from incomplete propellant combustion, deposited on the garment or skin surface around the entry hole at contact and near-c...