What is the difference between High Pressure Sodium and Metal Halide?
The difference between these two types of HID (High Intensity Discharge) lights is the color spectrum that is emitted from each. The High Pressure Sodium bulb emits light that is concentrated in the red to yellow side of the spectrum and are weak in the blue-violet end. While the Metal Halide bulb emits light that is very balanced and contains all the energy peaks at wavelengths of the visible spectrum. Visually the Sodium bulbs will appear very yellow-orange and the Halide bulbs will appear more blue-white in color.
