Blackening around the entry wound of a firearm injury is due to?

Smoke REF: Parikh 6th edition page 4.44 The soot or blackening is due to fine carbon paicles around the shot hole and can be readily wiped off the skin. The soot or blackening is due to smoke of black gunpowder and is comparatively less if smokeless powder is used. Note: Tattooing is due to both burnt and unburnt gunpowder