What is the negative?

A negative is a substrate used to obtain images in photography. The brightness of the obtained object image is opposite to that of the real object. In PCB terminology, the meaning of negative often refers to black and white negative. As for the brown "azo film", it was named by another photographic tool. The negatives used in PCB can be divided into "original negatives" and "working negatives" after copying. At present, the widely used negative film is coated with silver halide on the base of acetic acid film. When the light shines on the silver halide, the silver halide turns into black silver and is fixed on the substrate after the development process.

Development of negatives:

The research and development of color photography technology in China started too late, and Baoding began the trial production of color film in the 1970s. Due to poor quality and lack of matching cameras and processors, living space is lost. In the mid-1980s, foreign color photographic materials flooded into China and dominated the China market for more than 20 years, and the photosensitive material industry in China declined completely. 2 1 century, the rapid development of computer technology and the invention of ccd promoted the popularization of digital imaging technology and the complete decline of photosensitive chemical industry.