The role of light in ancient architecture photography?

Taking the facade image of the building is the most important image in the whole set of document images. Because of the huge volume of ancient buildings, it is difficult to use a group of huge artificial light sources for lighting, so sunlight is often used. When shooting, the light direction should be about 45 degrees, usually at 9- 10 in the morning and 3-4 in the afternoon. The light should not be too sharp, and it is best to cover the sun with thin clouds. When the light ratio (illumination ratio between bright and dark places) is too large to correctly reflect the details of bright and dark places, it is necessary to consider using flash or reflector to supplement the light and properly balance the contrast. The images of other facades are used as auxiliary images in the whole set of archive images, so the requirements for lighting control can be relaxed appropriately, but the details must be made clear, which is the basic requirement for images in ancient architecture archives (all cultural relics photography).

During the summer solstice, the sun is closest to the earth, and the sun often shines directly from the top of the head. At this time, it is not appropriate to shoot buildings with large eaves, because the proportion of light is too large and it is easy to hide the details such as colorful paintings and beams under the eaves. But at this time, when shooting buildings with few eaves, such as stone buildings and ancient pagodas, it is precisely because of the illumination of the dome light that the picture will have a strong three-dimensional sense and better depict the details of the building. In winter solstice, the sun is far away from the earth, and the sunlight is oblique, which can often illuminate the indoor depths of large-eaves buildings. At this time, the effect of shooting "big roof" buildings is better. In winter in the north, the "yellow roof" photographed at this time will be ugly because of the diffuse soot, poor air visibility and gloomy sky. The sunny weather and floating clouds in the intermittent thunderstorm in the south make the picture vivid and beautiful, but it also dilutes the theme of the picture and is not suitable for archival images.

It is difficult to shoot indoor images of ancient buildings, mainly because of uneven illumination, which easily leads to exposure transition near doors and windows, while the indoor corners are almost dark without illumination. At this time, we should carefully choose the shooting position and carefully study the fill light scheme.

In addition to being horizontal and vertical, shooting color painting images of ancient buildings must not have the requirement of geometric deformation, but also ensure the recording of color information. Because the color paintings are mostly under the eaves and the illumination is low, it is often necessary to use the car flash to fill the light. However, the brightness of the fill light should be appropriate. High-grade architectural painting often uses a large number of gilding and tracing techniques. A small amount of positive fill light can make the gold foil glow, and too much fill light will make the gold foil lose its color and form a bright spot. Pay attention when shooting.

For the murals on the wall, the picture is often large and the shooting depth is limited. Even with a wide-angle lens, the picture cannot be completely collected. At this time, it is often necessary to use splicing method to complete the recording of mural images. When shooting, we must pay attention to keeping the focal plane of the camera parallel to the surface of the mural, and at the same time, we must leave overlapping positions on the edges of the two frames to ensure seamless splicing in post-processing.

Proper use of light is an important technical condition to express the texture of building materials. Rational use of light is to control the direction and quality of light correctly (referring to the intensity and softness of light). Light can come from all directions, such as direct light (including front light, side light, backlight, top light, etc. ), scattered light, reflected light, etc. In direct light, the front light (commonly known as large flat light), top light and backlight are generally not conducive to expressing the texture of the building, while the side light (especially oblique light) can better express the texture of the building surface: when the texture of the building is rough (such as brick walls and rubble walls). ), the direction of oblique light is not very strict when shooting. As long as there is enough light from the side, the uneven surface will produce different degrees of light-receiving surface and shadow area, highlighting the texture of building materials, especially in the case that the building color is not rich, oblique light is very important to express the texture of the building; When shooting buildings with smooth external walls, the direction and intensity of oblique light are very strict. Starting from the principle that the incident angle of light is equal to the reflection angle, you must pay attention to the angle of light, the position of shooting point, the intensity of light and the softness of light when shooting a glass curtain wall building, and find the best combination to express the texture of its material.

2. The influence of light on architectural visual elements.

Understanding the influence of light on architectural visual elements is helpful to better express three-dimensional buildings with two-dimensional photos. Light energy directly affects the spatial form, scale ratio, texture and color expression of the building, and can directly affect the authenticity and artistry of the picture. Light can strengthen, weaken or even eliminate the performance of the above aspects. Generally speaking, the factors that light affects the vision of objects mainly include the direction, quality and color of light.

The direction of light refers to the direction of the light source relative to the building being photographed. Because the location of the building is fixed, the direction of light is very important for architectural photography. Buildings will have different shadow effects under the action of light sources in different directions. The light source in photography can come from all directions, and the light in each direction will affect the external characteristics of the building. As far as outdoor architectural photography is concerned, the light source mainly refers to the sun, and the light direction is mainly divided into front light, side light, backlight, top light and diffused light.

The quality of light mainly refers to the intensity and softness of light. The sunshine on a sunny day is very strong and has a strong sense of direction. Under the direct light, the building is rich in colors, which can produce strong shadows and strengthen the three-dimensional sense of the building. The position of the shadow produced by direct light will change with the relative position of the sun and the building being photographed, or with the position of the shooting point. The buildings represented by direct light are simple and rough, but they are often not refined enough, especially the detailed nodes in the shadows. The scattered light generated by reflection (such as light on cloudy days) is soft, usually without a clear sense of direction, and there is almost no shadow on the building, so the three-dimensional sense is poor, but the subject is really delicate and natural, and the influence of illumination angle on the picture is not considered when shooting.

Color of light

The color of light depends on the spectral components of light, that is, the wavelength of light. Sunlight is a mixture of continuous light waves with a wavelength of 400-700 nanometers. The color of sunlight will change with the change of time, climate, season and latitude, and people's color perception of scenery will also change. For example, when the sun just rises, the atmosphere contains dense fog, and when the sun goes down, the atmosphere contains more dust, so there are more red and orange light waves in the morning and evening, which makes the light in the morning and evening have a unique color.