The link between illumination and brightness as measured by luminance and illumination meters
So what is the difference between brightness and illuminance?
The concept of illuminance under the detection of illuminance meter:
In short, the total amount of light (luminous flux) emitted by the bulb enters a certain surface at a certain intensity - light intensity (light intensity), and then the luminosity of this surface can be measured.
The concept of luminance under luminance meter measurement:
Brightness refers to the physical quantity of the light (reflection) intensity on the surface of a luminous body (reflector). The human eye observes a light source from one direction. The ratio of the light intensity in this direction to the intensity of the human eye "seeing" the area of the light source is defined as the brightness of the light source unit, that is, the luminous intensity of the expanded area of the unit. When we stand at a position and look at a surface, we see the brightness level (brightness) of the surface.
To sum up: illuminance is an objective parameter, which is the total amount of light that we use to detect the actual arrival of a certain surface; brightness refers to the level of light emitted or reflected by the object perceived by the human eye.
Furthermore, the illuminance value is the same whether the surface is black or white, wood or stone. Surfaces reflect light, either specularly or more likely diffusely. Light refracts in many directions in space.
What impact do illuminance and brightness have on our lives?
It can be said that all indoor space lighting should evaluate the horizontal lighting of the work surface, but we should pay attention to the adaptability of lighting and color temperature. For example, in our work, it is not enough to change the color of the lights in the office, but it is also necessary to pay attention to the lighting.
▲High illuminance and low color temperature will make people feel very hot, while low illuminance and high color temperature will make people feel gloomy and tired, resulting in a decrease in work efficiency.
Relevant tests have shown that at the same time, with the increase of illuminance level between 300lx and 500lx, the satisfaction of workers will be significantly improved; the satisfaction of workers above 500lx is basically saturated, and the increase of illumination level will not significantly change workers' evaluation of the lighting environment. Therefore, China's latest office lighting standard is 300lx-500lx, which is also the most suitable illumination for the working surface.
In addition, in the dining space, there must be enough light in the indoor environment and the dining table to meet the basic dining needs of customers. According to the recommendations of the China Lighting Association in China's architectural lighting design standards, the lighting for the dining table should be 200 lx.
Chinese architectural lighting design standards require that the illuminance at the 00.75m plane of the Chinese restaurant shall not be lower than 200lx, and the western restaurant shall not be less than 100lx, and the illuminance value of each space position.
