Museum lighting requirements for illuminance, chromaticity, glare, etc.

In museum lighting, the exhibits displayed in each showroom are not the same. Different types of exhibits have different sensitivity due to their different materials, colors, etc. Different exhibits need different light to set off the display effect. Therefore, the general illumination of the showroom should be determined according to the category of the showroom. Select the appropriate illumination for the display to achieve a good display effect, as shown in the following table.

In general, the level of visual adaptation is related to the average illumination of the site. The uneven distribution of illumination on the exhibits, and even the appearance of uncomfortable dark areas or light spots, will affect the mood of the audience. In China's "Museum Lighting Design Code", the following requirements are put forward for the uniformity of illumination:
(1) For plane exhibits, the ratio of the minimum illuminance to the average illuminance should be greater than or equal to 0.8, but for plane exhibits with a height of 1.4m, the ratio of the minimum illuminance to the average illuminance should be greater than or equal to 0.4.
(2) For showrooms with only general lighting, the ratio of the minimum illuminance on the ground to the average illuminance should not be less than 0.7.

color temperature
It is particularly important to shape the atmosphere of the scene in the museum lighting and the presentation of the color and material of the exhibits. General museum lighting is recommended to use a light source with a color temperature of less than 3300K, while maintaining the color temperature integrity of the unified environment.
According to the research results of Zhejiang University Color Engineering Center experts on what kind of illumination and color temperature combination in museum lighting is comfortable, as the color temperature becomes higher, the observer will have a colder perception; the increase of illumination can make the environment brighter; The influence of illumination on museum lighting is greater than the influence of color temperature on it. The results show that, in general, the color temperature change in the range of 2850K-4000K and the illumination change in the range of 200lux -800lux can create a comfortable and pleasant LED lighting environment in the museum.

Glare
Glare is one of the important elements of museum lighting. In the museum lighting design, any glare phenomenon will affect the audience's careful observation of the exhibits. It is necessary for the museum lighting design to eliminate all kinds of glare in the audience's field of vision as much as possible. The LED luminous body is concentrated, most of the light is concentrated in the center, and the divergence angle can be controlled to a high degree, which can control the emitted light to the greatest extent, reduce glare, and simplify the structure of the lamp, save shading equipment, so it is suitable for the focus of the exhibits or local lighting, and can realize dynamic art lighting. The anti-glare design and reasonable arrangement of LED lamps can greatly avoid the direct glare caused by the light directly hitting the human eye and causing discomfort.

Glare includes direct glare, reflected glare, contrast glare. The anti-glare design of the lamp can greatly reduce the direct glare. In addition, for the direct glare generated by the light source, the method of controlling the incident angle of the light and adding a shutter on the lamp can be adopted to eliminate the light directly entering the eyes of the audience. Generally speaking, the 30 ° incident angle can not only effectively avoid glare, but also help to shape the three-dimensional sense of the three-dimensional exhibits, so it is called the museum angle.
For the reflection glare caused by the glass showcase in the expo lighting, a reflection image area without light source should be determined after calculation according to the relationship between the incident angle and the reflection angle, and the light emitted by the light source should be controlled in this area to ensure that there is basically no reflection glare entering the eyes of the audience. To eliminate the reflection and shadow on the glass surface of the showcase, one is to adjust the illumination angle of the light source, and the other is to ensure that the brightness of the surrounding environment is lower than that of the showcase. Accurate optical and lighting design can avoid contrast glare caused by uneven brightness distribution and improper control.

Color rendering
The color rendering of the light source directly affects the hue and saturation of the exhibits. In order to restore the true color of the exhibits, the light source is required to have very good color rendering (Ra), and the color rendering index is generally greater than 90. The lights with high color rendering index can truly present the original appearance and color of historical relics, truly present the civilization left by ancestors in front of the audience, and shorten the distance between the museum and the audience. LED lights with a color rendering index of up to 95 can more truly present the original appearance, texture, detail technology and color of the exhibits.

In addition, during the museum visit, the comfort (Comfort), flexibility (Vividness) and clarity (Definition) of the lighting in the museum are particularly important to the visual perception of the observer.
A single architectural configuration or a single lighting design cannot complete the lighting design very well. It must be comprehensively considered from two aspects of technology, sightseeing and the psychology of viewers, and strive to apply more modern new technologies and new concepts to the lighting design of museums. In addition, it should be noted that the appearance design of lamps should be coordinated with the style of buildings in the process of displaying the theme, avoid being incompatible with the lighting design environment of the museum building. In order to create a life, full of vitality, feel realistic, the overall optimization of the light environment, to meet the display and protection of the lighting requirements.