All the great colors that fireworks poses would make it seem simple to achieve but it is actually very complex. The colored points of light emitted when fireworks explode require an oxygen producer, fuel, color producer, and a binder to keep everything in its place. It takes a considerable amount of talent and physical science to formulate a firework to produce color and just the right amount of brightness. Color in fireworks is produced in two ways. One is through Incandescence and the other is through Luminescence.
When light is produced from heat it is called Incandescence. When a substance becomes hot it produces light. As it gets hotter it produces a different color of light. First it will produce infrared light. Then as it gets hotter and hotter it will produce red, orange, yellow, and last it will produce white. Some metals burn very bright/hot such as titanium, aluminum, and magnesium. Metals are added to fireworks when high temperatures are needed to produce the desired color. The temperature of the colors are as follows: faint red 890F, dark red 1070F, red/orange 1340F, bright orange 1700F, orange/yellow 2060F, yellow/white 2420F, and white above 2600F. Greens and blues require much higher temperatures that couldn’t be produced in fireworks.
Producing light without heat is called Luminescence or cold light. Luminescence can happen at or below room temperature. Here’s how it works. Energy is absorbed by the electron of a molecule or atom. This causes the electron to become excited but also unstable. When it returns to its lower energy state a photon is released. The color of the photon is determined by its energy. The definition of a photon is: a quantum of visible light or other form of electromagnetic radiation demonstrating both particle and wave properties. A photon has neither mass nor electric charge but possesses energy and momentum (Source: Encarta Dictionary: English). Some of the compounds needed to produce the correct color are unstable at low or high temperatures. In order to solve this problem they are combined with something more stable. It is quite difficult getting different components to mix for stability while still producing the desired color and brightness. The following are the compounds used for the different colors: sodium nitrate and cryolie produce yellow, iron with charcoal and carbon produce gold, barium and barium chloride produces green, copper and copper acetoarsenite produces blue, strontium carbonate produces red, titanium or magnesium powder produces silver, magnesium or aluminum barium oxide produces white, calcium chloride and calcium sulfate produces orange, and purple is produced by making red and blue light together.
The quality of ingredients in a firework can make a huge difference in the color and brightness. Have fun with the fireworks this year since a lot of work went into making all the great colors.