What does negativity mean?

Negative films are classified according to photosensitive speed, from ISO25 with the lowest speed to ISO3200 with the highest speed. Generally speaking, the lower the photosensitive speed, the finer the image quality. According to the film size, 120, 135, 1 10 are commonly used, and there are also large-format negatives such as 4x5 or 8x 10 for shooting advertisements or large posters.

There are black and white negatives, color negative, infrared negatives and so on. Color negatives adjust the tone of photos according to different light sources, which are divided into sunlight films and lighting films. If you use lighting film to shoot a scene in the sun, the tone of the photo will be blue.

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.