Stadium lighting can actually be regarded as an extreme functional lighting, which requires different parameters from other ordinary lighting. Ordinary functional lighting includes illuminance, uniformity, color temperature, glare index, etc. For example, the illuminance of the desks in the classroom reaches 300lx, the illuminance of the blackboard reaches 750lx, and the uniformity is 0.8.
However, stadium lighting design is different. For example, Olympic Stadium, OBS has a general manual for lighting requirements. Each competition has a separate booklet, which requires horizontal illuminance, vertical illuminance, and glare requirements for each area. There are even illuminance gradients, which require an incomparable level of detail.
First, illumination target. The target of the stadium lighting is to allow us to observe what is happening on the field very clearly, without any problems such as trailing shadows or delays when photographers take pictures. Good lighting is to let people forget its existence. Once the lighting on the field is concerned, it means that the lighting is not very good, because it has affected others, and even affects the game.
Second, balance rules. When we do some non-functional lighting, as long as there is no breakthrough in the framework of national norms, we can give full play to this range. But stadiums lighting hardly has much space to play, there are restrictions everywhere. Because the current stadium lighting, especially for high-level events, itself is already balancing many things. For example, balancing the needs of athletes, balancing broadcast requirements, balancing the experience of live audiences, balancing cameras, and balancing advertising boards… This balance has reached a critical point. This critical point is to meet the basic requirements, but neither party will be too comfortable. If we overplay at this time, it is very likely that this balance point will be broken, so we can only design within extremely strict regulations.
Third, evaluation criteria. Ordinary lighting evaluation criteria is people-oriented, the purpose is to make people feel comfortable visually. But for stadium lighting, it is not only to meet the special needs of some special equipment. For example, the difference between the color rendering index Ra and TLCI is nothing more than adding a group of saturated colors (R9~R14) even in the LED era. However, this part will cause some problems when put into the TV equipment, because the structure and sensitivity of the TV equipment are different from that of people, so another set of color evaluation methods are adopted. This is what we call TLCI — TV Lighting Consistency Index.