Luminous flux is the total visible light energy radiated per unit of time from a light source. It is the most important lighting characteristic of light sources in the field of lighting technology.

Colour temperature is actually a colour sensation caused by visible light in humans. It is compared to the radiation of a black body, which absorbs all the energy, i.e. all the light falling on it. It is measured in Kelvin. As the colour temperature increases, the red components of light decrease and the blue components increase, so the higher the colour temperature of light, the 'bluer' it becomes, and the lower the colour temperature of light, the 'redder' it becomes.