The lighting function of the light area of stage lighting and its artistic function are the main content of this paper. Generally speaking, the light area is for a stage, which constitutes the basis of drama stage vision, and the whole lighting art can give play to the interpretation of technology and art on this basis. Light areas exist from darkness. Each light area forms an independent or associated three-dimensional space, which plays a decisive role in basic lighting or artistic rendering of atmosphere.
1、 Overview of light region
（1） Overview of light area
Light area refers to the area projected onto the stage space and its distribution . From the light source of lamps and lanterns to the mapping area (stage, scene, water surface) projected onto the theater materials are the scope of light area. As an important part of stage art, light area generally plays two roles: one is to maintain the basic lighting function of the whole drama, give a special space-time construction function to the specific space environment such as the theater, and present the real performance of the actors on the stage in the eyes of the audience; Second, it plays the role of rendering the whole art, including the shaping of character modeling, the treatment of light area and light and shade, and the treatment of light area and color. It is not only a rendering of the tone of the whole drama, but also a visual description of specific environmental characters.
（2） Association between light area and lamp
The first thought of the generation of light area is to create its light source, that is, lamps. Various lamps can project a variety of light areas. These lamps directly affect the color temperature, brightness, virtual reality, saturation and even color of the light area. The light area projected by various lamps can play various lighting or artistic rendering functions.
Stage lamps and lanterns are a huge system, which can be divided into three categories according to the characteristics of Optics: stage astigmatism lamps and lanterns, stage spotlight lamps and lanterns and stage special lamps and lanterns.
1. Stage astigmatism lamps have a large range of projected light area, low illumination, and the edge of the light area is relatively empty, such as stage sky curtain astigmatism lamps and strip lamps. The light area projected by such lamps is usually used to illuminate or pave the tone for the main performance area or scenic spot. However, due to the large area of the projected light area, such lamps are generally not used if there are detailed light area changes in the performance area.
2. Stage spotlights. The light area projected by these lamps is relatively concentrated, the illumination is relatively high, and the boundary of the light area is relatively solid, with obvious contour. Such as stage spotlight, imaging light, downlight, spotlight, etc.
3. Special stage lamps. These lamps mainly refer to special lamps that can produce various light areas. The light areas projected by them can be various light projections, images, special beams of different colors to show specific stage lighting effects. Moreover, the light areas projected by such lamps, such as computer lamps, can make rapid movement through computer programs, Repeat the motion process of a simple light region many times. Such as stage projector, projector, scanning computer lamp, etc.
2、 Basic function of light region
In fact, the basic purpose of setting the light area is to play the role of lighting. Lighting the performance of actors, and making the stage picture clear in primary and secondary, rich in levels, flexible and changeable, which can be displayed on the same stage.
The lighting function of the light area is all for the eyes of the audience. People's eyes have great adaptability to light and can enlarge and contract, so we should pay attention to two places.
1. In a specific stage environment, grasp the contrast of light intensity in the light area. For example, in a black field environment, a bright performance area is highlighted. At this time, the visual nerve is most sensitive to this brightness. Similarly, when a beam of chasing light hits the stage in a dim light, we will feel very bright, but when the whole field is bright, we will feel that the light intensity will be very weak, What the audience pays attention to is closely related to the ambient lighting.
2. The change of lighting in the light area after a long period of visual adaptation can greatly stimulate our visual nerve. People's pupils gradually adapt and enlarge in the dark for a long time. At this time, when the light field suddenly comes on, we will feel that the environment is particularly bright. On the contrary, when the dark field suddenly comes on in the bright environment for a long time, the audience's eyes will feel dark, This phenomenon is commonly referred to as "bright adaptation" and "dark adaptation".
3、 The artistic expression function of light area on the stage
（1） Light area and light and shade
The essence of the brightness of the light area is the light intensity of the light area under the projection of the light source. The brightness of the light area is a very important link. To deal with the brightness of the light area is to deal with the relationship between the light and the setting, and the relationship between the light and the character modeling. Light area and light and dark are separated from light area lighting, mainly because light area and light and dark emphasize more artistic expression and take the audience as the main body, while light area lighting mainly aims at the audience's visual system and takes the audience's eyeball as the main body, playing a basic technical role. The light and shade of the light area are related to the director's scheduling, set design, character modeling and the actor's self feeling of light and darkness in the specified scene.
（2） Light area and color
The following points should be paid attention to when setting the color embodiment of the light area:
1. Set the main color tone of the light area where the character is located. The main tone should be clear and direct. The color of the same main tone is to give the whole drama a tone, directly reflect the theme of the drama, give a hint to the audience's psychology, and associate it with the changing characteristics of the characters' psychology on the stage. The main tone should be dominated by one color and supplemented by other colors.
2. While rendering the color of the light area, we should take into account the stage atmosphere and actor lighting, realize the unity of technology and art, integrate the characters and scenery on the stage, and highlight the performance of the actors.
3. The color design of light area shall be mutually negotiated and unified with the clothing and makeup design on the selection of color, and the light color and search shall be perfectly combined. The color facilities in the character light distribution area should be diversified.
（3） Light zone's treatment of time and space in stage drama
1. Creation of specific space-time environment in light area
The light area setting of an area is directly related to the content of the drama, the number of sessions and the size of the theater. The size and depth of the whole theater determine its light area distribution. The depth of the whole stage determines the number of light rows. The space level determines the number of lamps in each row. The number of light rows in the theater is directly proportional to the size and depth of the stage. When setting the light area, the number of lamps should be determined according to the length of the starring area. When rendering the atmosphere, the light area and the light area sometimes need to be connected together. Because the light source of the downlight, that is, the design of the bulb, is vertical and horizontal and rotatable, the rotating light source can be adjusted according to the needs of the performance area, artistic rendering and the specific situation of the plot, Make the light area uniform. Sometimes they are separated from each other to form sheet-like single light areas, which are presented according to the needs of each drama.
2. Juxtaposition and interleaving of light region and space-time
When discussing the construction of stage space, we should involve a theoretical definition - the assumption of space. The limitation of stage space produces the assumption of stage art, and only assumption can conquer the limitation of stage space. In fact, hypotheticality is a manifestation of the initiative of the creative subject. It is not a simple formalism. It creates the illusion of reality on the stage. This is the aesthetic idea that the naturalistic movement from the Renaissance to the end of the 19th century has been dreamed of by Western stage artists. Any art has a presumption, but the nature and degree of the presumption of each art are not the same. For example, stage lighting uses the light area to create an environment beyond time and space, and highlights the light area through the relative black field. The light area can be a constantly changing space-time environment. Actors can see the past, see the future, and talk to each other beyond time and space.
The light area has a juxtaposition relationship with two time and space on the stage. What is juxtaposition is to create a scene beyond the boundary of time and space through two non-contact light areas, place two different time and space environments on the stage at the same time, and there are two or more main performance areas at the same time. Such juxtaposition of time and space makes the conflict of drama more strongly reflected. For the alternation of time and space in the light area, for example, setting one or several actors to perform in two alternating light areas can even easily complete the stage scheduling at different times.
In a word, the light area is inseparable from the light intensity, light color, light level, light shadow, light movement and scene changes of the whole stage drama. We should combine the law of life to make the stage more natural and transform it objectively and unconsciously. At the same time, we should also change the light with the scene and the light with the emotion, pay attention to the expression of inner emotion, and let the audience feel the light talking and performing.