Meaning of Scotopic/Photopic Ratio of Light Sources in Lighting of Outdoor Spaces

This paper deals with the issues of meaning S/P factor of light sources in lighting of outdoor spaces. The first part describes the problem of photopic, scotopic and mesopic vision, as well as functions and activities of the human eye which define the meaning of the S/P factor lamps. The second part is dedicated to the measurement of luminous flux a selected light source used to lighting outdoor spaces, calculating S/P (scotopic/photopic) factor and ELF (Effective Luminance Factors) and finally to drawing conclusions from their measurements and calculations.