Pyrotechnic smoke for practical use can easily be obtained from a simple smoke device without any special technique, and must be safe to handle. Here, only the smokes which are used for fireworks are discussed.
The processes classified as follows:
1. The burning grows to form a mist which absorbs the moisture from the atmosphere. Smoke composition, for example. The hexachloroethane smoke composition creates a vapor of zinc chloride or aluminum chloride, which becomes white smoke when it combines with moisture in the air. At present carbon tetrachloride smoke composition is seldom used.
2. The material is first vaporized by the heat of combustion and then condenses again to fine solid particles which creste smoke. The white smoke caused by sulphur and yellow smoke caused by realgar belong to this type.
3. Smoke cause by incomplete of a composition. This type of smoke is widely used as black smoke in fireworks. It utilizes the carbon particles created by the incomplete combustion of naphthalene or anthracene.
4. Colored smoke produced by vaporizing dye. A volatile dye is first vaporized and then it condense the fine solid particles, which look like colored smoke. Generall this kind smoke shows its own beautiful color by reflected light, but it looks dirty when the light is weak. In a cloudy sky it does not have a good color. Generally the color of the aqueous solution of dye from permeated light is the same as the color of cloudy solid particles in reflected light. Physically it is an interesting problem.