There White light has advantages in public lighting and in applications concerning the urban landscape. Advantages that materialize in energy saving, better aesthetic quality, safety and accident prevention. If then the White light is generated by solid state lamps, in particular those a LED technology, the benefits are even greater.
The issue is interesting if we consider that in Italy today there are about 9 million lighting points in public installations, which in 60% of cases use low-efficiency technologies such as mercury vapor lamps. If it were used in public lighting for monuments, squares and streets White light with more efficient solutions, for example the solid state light, the savings for the community would be enormous.
White light and energy saving. People perceive the White light as brighter and this makes it possible to obtain the desired lighting with a reduction in the luminous flux and consequently with a lower amount of energy.
White light and aesthetic quality. The white light brings out the best of the night urban landscape. It also integrates with both modern and traditional building materials and gives green spaces a vibrant and lush look.
White light and safety. Thanks to the superior color rendering, white light makes it easier to distinguish objects, colors, shapes, faces and details making them more reassuring. The ability to facilitate face recognition is a deterrent to crime.
White light and accident prevention. The white light contributes to road safety by allowing early detection of road side movements and recognition of dangerous situations from a greater distance.
But what is the White light? Without getting lost in the discourses on the physics of light, let's say that it depends on the so-called 'color temperature', which is measured in Kelvin and is a reference used by lighting engineers and photographers to quantify the hue of light.
There White light has a high color temperature. At a low temperature, around 2000 Kelvin, the orange color corresponds, going down you go to red and infrared (no longer visible) while going up you go to white, blue, violet and ultraviolet (no longer visible) . A warm light corresponds to a low color temperature, vice versa a higher temperature produces a defined cold light.
To delve into the nature of light, also from the physical point of view, we observe Newton's Prism