High-speed black-and-white film has the following characteristics

For the user, the most practical problem is that the high sense of film price is high and not easy to buy, the preservation period is shorter than the low-speed film, the photo can use a slightly higher shutter speed, the impact of the impact of the texture is slightly worse, will show the obvious silver salt particles. The reality is that there are very few varieties and models of film on sale, usually ISO100 (GB21), and then higher may be ISO200 or 400, compared to the ability to enhance the digital camera is very limited, to solve the problem of shooting space is not much.

In the case of less than high-sensitivity film, you can use ISO100 medium-speed film to artificially increase the sensitivity by 1 to 2 stops through the "sensitization" process to act as a high-sensitivity film. Specifically, it is to intentionally reduce the exposure (according to the need to increase the shutter speed or reduce the aperture), and then increase the intensity of the development of the processing (slightly increase the temperature or the appropriate extension of the processing time), so that after the effect will be affected by the characteristics of the film itself and the processing experience and different, you can try.