Maintaining good color recognition from high-pressure sodium lamps
, Bullough says, can be achieved by using at least 3 footcandles of illumination.
In vegetable leaves exposed to light generated by the solid-state illuminator, nitrate concentration was reduced by two to three times in comparison with those kept under high-pressure sodium lamps
Consumers can still find mercury in high-pressure sodium lamps
, fluorescent bulbs, some thermostats, spent batteries, sphygmomanometers, thermometers, dental amalgams, chemicals, and staining solutions.
According to Forster, HID light sources, such as metal halide and high-pressure sodium lamps
, have long dominated the market for outdoor lighting and lighting indoor spaces with high ceilings.
The high-pressure sodium lamps
provide even higher light output per watt than metal halide (50 to 150 lumens per watt), with a golden yellow light.
High-pressure sodium lamps
have supplanted incandescent bulbs and use only 30 percent of the energy.
While some high-pressure sodium Lamps
have a CRI of 22, which means They render colors poorly.
The columns are fitted with high-pressure sodium lamps
which emit a golden white light rather than the orange light of typical low-pressure units.
Illumination is provided by metal halide, metal halide pulse-start or high-pressure sodium lamps
in wattages between 600 and 1000.
Mark Norcross, electrical designer, Archer Engineers (Springfield, Missouri), specified Mongoose(r) luminaires from Holophane Corporation (Newark, Ohio) with 250-watt high-pressure sodium lamps
Fixture heights range from 28" to 48" and are available in 35W to 100W metal halide or high-pressure sodium lamps
Union square Park's historic light fixtures were outfitted with high-pressure sodium lamps