Imaging of aerial photography

Aerial camera images the ground in the air, and the imaging process is the same as general photography. That is, the reflected light (visible light) collected by the lens is directly exposed on the photosensitive film through instant exposure of the shutter, forming a latent image of a negative image, and then the negative image is obtained through development and fixing technology. Then through contact printing, development and fixing, the (positive) image consistent with the brightness of the ground object is obtained, that is, the aerial photograph.

The image in the aerial photo is due to the different light intensity reflected by different parts of the ground object, which makes the sensitivity of the photosensitive material different, resulting in different colors (black and white) in different parts. Photosensitive materials (whether photographic film or printing paper) are mainly composed of photographic emulsion layer and film base. The emulsion layer consists of silver halide, gelatin and photosensitizer. Black-and-white film for ordinary photography is generally full-color film, which can feel all visible light (but has poor feeling for green light). The photosensitive layer of black-and-white infrared film contains substances that feel infrared light, which can directly record near-infrared light invisible to human eyes. Color film is composed of three layers of emulsion sensitive to blue, green and red wavelengths, and can feel all visible light. After exposure and development, a negative film complementary to the color of the ground object is formed, and it is restored to a natural color photo after contacting with color printing paper.

In aerial photography, it is necessary to choose sensitive materials with high sensitivity, moderate contrast and high resolution. In order to obtain high-quality aerial photos with clear images and rich levels.