Comparison between LED & HPS lights
Color Rendering of LED & HPS
The CRI of white LED is over 75, while that of well-encapsulated LED reaching 98, which makes the color of the objects lightened appear natural.
The CRI of HPS is much weaker, with a CRI less of 23, and the objects lightened appear reddish.
Color Temperature of LED & HPS
The color temperature of LED ranging from 2600k to 10000k.According to different functional lumination requirements, there are warm white, pure white and cold white for option.
The color temperature of HPS ranging from 1950k to 2250k.With a reddish light, it makes people feel warm.
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, and other fields. The color temperature of a light source is determined by comparing its chromaticity with that of an ideal black-body radiator. The temperature (usually measured in kelvins(K) ) at which the heated black-body radiator matches the color of the light source is that source's color temperature; for a black body source, it is directly related to Planck's law and Wien's displacement law.
Counterintuitively, higher color temperatures (5000 K or more) are "cool" (green–blue) colors, and lower color temperatures (2700–3000 K) "warm" (yellow–red) colors.
In road lighting, the light penetrability mainly refers to the ability of penetrating through rain and fog.
The effect of foggy or rainy weather on the road lighting is reflected in that the light scattering of the suspended particle in the fog and the raindrop debases the penetrability, which leads to the drop of illumination intensity directly. The relevant theory is based on Rayleigh’s law of scattering and G. Mie.P.Debye’s law. The application scope of visible light scattering law is listed below: r represents the particle’s radius. When r<0.037 µ m, Rayleigh’s law of scattering works; when r>0.037µ m, G. Mie,P.Debye law comes into effect. The light scattering effect of Rayleigh’s is connected with wave length, while that of G. Mie,P.Debye is not. The radius of suspended partial in the fog and rain is as follows: 2.8µm~10µm in the fog, 10µm~5000µm in the raindrop. Since the particle radius is far over 0.037µm, there exists no connection between the light scattering and wave length in foggy or rainy weather, i.e., there lies no connection between the penetrability of road lighting and the color of light.
Therefore, the penetrability of LED is the same as that of HPS lights.
98W LED Street Light vs 250W Sodium Lamp
|LED ：high CRI||HPS：low CRI|
112W LED Street Light vs 250W Sodium Lamp
|LED Light: white light, clear||Sodium Lamp: yellow, unclear|