Talking about the three important issues of museum lighting design!
The lighting design of the museum should pay special attention to three aspects: the protection of the exhibits; the visual presentation of the exhibits and exhibition space; and other design, engineering and maintenance issues.
01Protection of exhibits
1.1 Control infrared radiation and ultraviolet radiation.
By choosing a light source that does not contain infrared or ultraviolet radiation, or installing a lens that can filter out infrared or ultraviolet radiation, the infrared and ultraviolet radiation brought by the illumination can be reduced as much as possible.
1.2 Limit illuminance and annual exposure.
The light sensitivity of different types of exhibits varies greatly. According to the "Museum Lighting Design Code" (National Standard of the People's Republic of China GB/T 23863-2009), compare the lighting design codes of other national museums, and select the illuminance and annual exposure standards suitable for the specific project. According to the standards, the exhibits are classified according to light sensitivity, and accordingly, the illuminance and annual exposure limit values for each exhibit are determined.
02Visual presentation of exhibits and exhibition space
2.1 Visual adaptation.
This is an important and often overlooked issue. From the outside of the museum, to the entrance hall and transportation space, to the exhibition hall and exhibition hall, to different parts of the exhibition hall, there may be great differences in brightness. Moreover, the usual situation is that the brightness in the exhibition hall is low, and the brightness of the area outside the exhibition hall is high. The audience enters the low-brightness environment from the high-brightness environment. If the conversion speed is too fast, the vision will not adapt. Moreover, the corresponding brightness is from high to low, but the content is from secondary to primary, which is contrary to the psychological expectations of the audience. Therefore, in the spatial sequence before entering the exhibition hall, the brightness should gradually decrease to a level lower than the brightness in the exhibition hall, or at least close to the brightness level in the exhibition hall.
To achieve such an ideal brightness transition, it is necessary to start the spatial brightness planning of the entire museum at the beginning of the architectural design. The brightness distribution in the exhibition hall is closely related to exhibition planning and exhibition design. For example, the brightness distribution may be very different for exhibitions conducted by chronology and exhibitions conducted by materials. Chronological exhibitions may put a piece of bronze and a piece of colored silk together. The illuminance limits of the two are very different (300lx and 50lx), which may cause an excessively high brightness ratio in a field of view, which is a problem. It needs to be solved from the perspective of exhibition design or lighting design. Exhibitions based on materials, such as bronze exhibitions or silk exhibitions, may not encounter such problems.
2.2 Acquisition of exhibit data and spatial interface data.
The lighting design should be a brightness design, that is, a design aimed at intuitive visual results. To design the brightness, the shape and material data of the exhibits (such as 3D model, color, finish, reflectance), the shape and material data of the exhibition space and interface are all necessary prerequisites for lighting design.
2.3 The creation of the light environment atmosphere of the exhibition hall.
The lighting of the museum, especially the lighting of the exhibition space, has different styles. The lighting style of the exhibition space largely depends on the architectural style and exhibition style. The space and display method may be a completely calm and objective background, or it may be a narrative and story-like character. The lighting will adopt corresponding methods and form corresponding styles.
In addition to matching the exhibition style, in a museum, it is another important function of lighting to relieve exhibition fatigue by creating or changing the atmosphere of the light environment. The introduction of natural light, or the introduction of natural light impression, has a very positive significance for the creation of the atmosphere of the museum's light environment. Of course, the introduction of natural light must be effectively controlled to ensure that it does not cause damage to the exhibits.
2.4 The lighting of the showcase.
Due to the limitation of the internal space of the showcase, the selection of lamps and lanterns in the showcase, the setting position, and the light projection angle are all greatly restricted. If the display cabinet design and lighting design cannot be carried out on the specific exhibits, it is difficult for the lighting in the display cabinet to achieve the desired effect. For the needs of exhibit protection or scene setting, the lighting control in the exhibition cabinet may be incorporated into the entire exhibition hall lighting control system, and the control mode and wiring should be considered as early as possible.
The reflected glare on the glass surface of the showcase is another key factor affecting the lighting effect of the showcase. The use of low-reflective glass to control the brightness of the entities on the opposite side of the glass and the space (the audience passing through the space) is an effective means to control the reflected glare. When the glass surface of the showcase is opposite to other exhibits, it is very difficult to control the reflected glare.
2.5 Meet the flexibility of exhibition.
Museum lighting should have a certain degree of flexibility to meet the needs of exhibition adjustments and temporary exhibitions. The flexibility includes the flexibility of the power transmission location, the flexibility of the illuminance distribution, and the flexibility of the control equipment settings (mainly the flexibility of the induction equipment settings).
2.6 Glare control.
The level of glare control has a decisive influence on the visual quality of the museum. In the lighting of the museum, glare roughly includes three types:
Direct glare, mainly the glare directly produced by the lamp, such as the light-emitting surface of the lamp in the normal field of view;
One-time reflected glare is mainly caused by the virtual image of the light-emitting surface of the luminaire. For example, the virtual image of the light-emitting surface of the luminaire is seen on the relatively smooth surface of the exhibit or the glass surface of the showcase, and the exhibit cannot be seen clearly;
Secondary reflection glare, that is, the glare produced by the virtual image of the illuminated object, such as the virtual image of other exhibits on the glass surface of the showcase, but the exhibits in the showcase cannot be seen clearly.
By choosing lamps and anti-glare accessories, you can eliminate or weaken direct glare, such as choosing lamps with deep light sources, installing anti-glare grilles, honeycombs, adjustable angle visors, etc.; by controlling the projection angle, you can eliminate or Reduce direct glare and one-time reflected glare, such as making the angle between the projection direction and the horizontal plane greater than 60 °, so that the light output of the luminaire has less impact on the normal field of view; by controlling the reflective surface of the glass showcase and other entities and spaces (through The brightness of the audience in the space, so that the brightness of the virtual image is lower than the brightness of the viewing object, so as to eliminate the secondary reflection glare
03Other design, engineering and maintenance issues
3.1 The choice of control mode.
The control system, including the sensor system, plays a key role in exhibit protection (such as controlling the annual exposure), scene setting, and lighting debugging. The current common control methods include on-off switch by loop, dimming by loop, and single lamp dimming (dimming through the control system, non-manual dimming). Correspondingly, the possibility of setting the scene is determined. Different control methods have different requirements for line laying methods and equipment selection. In particular, line laying is usually completed at an earlier stage of the project, and it is required to determine the control method as soon as possible.
3.2 Convenience of debugging and maintenance.
In the museum, the lighting system is usually set on the ceiling, and the debugging and maintenance methods of the lighting equipment should be considered at the design stage, such as setting up horse tracks and even ceilings. When it is not possible to set up a horse track and a ceiling for the upper person, a lift truck that is easy to operate should be used.
Another important factor affecting commissioning and maintenance is the control system. If a single-lamp dimmable control system (DALI, digital addressable lighting interface) is used, the light intensity of a single lamp can be changed on the ground when dimming; when the equipment fails, the system can give a reminder, and Find out the cause of failure more quickly and accurately.
3.3 The spacing and direction of track settings.
The exhibitions of museums are uncertain, and lighting should be able to respond flexibly. The setting of the track has a decisive influence on ensuring the flexibility of lighting. There are two most basic criteria for testing whether the layout of the track is reasonable:
One is the coverage of the museum space by the reachable area of the light intensity center when the angle between the projection direction of the lamp and the horizontal plane is not less than 60°. If it cannot cover at least 2~3m above the ground, the track spacing is too large.
The second is at least for the known vertical surface, whether there is a reasonable location for the wall-washing lamps (because the wall-washing lighting has relatively fixed requirements for the arrangement of the lamps and the distance to the vertical surface). The track setting is highly related to architecture and interior design, so lighting needs should be fully considered as early as possible in architecture and interior design.
3.4 Field experiment and model test.
Since lighting has a vital impact on museums, in the lighting design of museums, lighting experiments should be carried out as much as possible to simulate the real exhibition state on the spot. Especially in an environment with many showcases, check the secondary reflection glare and the shadows formed by the showcases on the wall and the ground. When there are no conditions for on-site experiment or proportional simulation, the simulation of the solid model should be carried out.
The ideal lighting design of the museum is embodied in the two goals of lighting design, one is to design the brightness, and the other is to design the lighting for each exhibit in a targeted manner. The purpose of brightness design is to determine the brightness of the illuminated object, not just the illuminance. Targeted lighting design for each exhibit is the hope that the exhibits will be fully expressed.
