Re: How does the dye and phosphor coating create the black light effect?

Hi Kristen! This is about: Re: What gases are in a black light bulb

Blacklight tubes are a type of fluorescent tube. They don't use a filament like incandescent bulbs do. Their light comes from a kind of electric spark. Blacklights are basically the same as all other fluorescent tubes, but they lack a white phosphor coating inside. All fluorescent tubes (even the white ones) naturally create ultraviolet light.

The main chemistry of a blacklight bulb involves the mercury gas. It works like this:

1. Pump the mercury atoms full of chemical energy
2. This causes the electrons in the mercury atoms to make quantum leaps to higher orbitals
3. Eventually the electrons fall back down to their old orbital levels
4. When they fall, they lose energy
5. The lost energy is emitted as light
6. The frequency of the light is determined by the change in electron energy, which is determined by the difference in energy between the high orbital and the low orbital levels
7. Mercury happens to emit ultraviolet light.

Mercury gas happens to emit ultraviolet light. It also emits green and blue light. If the blacklight tube was made from clear glass, it would create ultraviolet light, but it would also emit green and blue (it looks gray-violet to the eye.) To get rid of this visible light, a special dye is mixed into the glass (I don't know what chemicals are in this dye.) The dye blocks the green and blue visible light, but lets the ultraviolet light out.

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