“Color is joy,” said Ernst Haas, the most famous and influential photographer of the 20th century. In the 1960s, when the “most serious” photographers only wanted to see the world in black and white, this pioneer of color imaging was the first to use Kodak film to express the undeniable power of color.

At the same time, French volcanologists Katia and Maurice Krafft used 16mm lenses and Nikon F2 film cameras to record the thrilling movement of active volcanoes, with the orange-red magma gushing out like blood flowing in the heart of the earth.

The development of optical imaging technology has greatly expanded human vision and expression capabilities, but it is difficult for humans to get out of the dilemma of color. We cannot see everything in the night as freely as in the daytime, although most magic happens at night.

1. Human Eye, ISP and Digital Imaging

The inspiration of optical imaging technology comes from the observation of human visual activities. When the photons entering the eye hit one or more of the 12.5 billion photosensitive nerve cells in the retina at the back of each eye, visual processing begins:

Humans have about 130 million rod cells, which use rhodopsin to receive weak light, help us perceive brightness changes of specific light intensity, and also dominate our visual function in low light at dawn and dusk and at night.

The wavelength range of visible light is 380-790 nanometers, which is also the only wavelength range with color information.

Compared with the powerful rod cells, humans only have about 7 million cone cells. Cones rely on related photosensitive pigments to distinguish colors, and they can only work properly when there is sufficient light.

If it is in a particularly dark environment, the cones will stop working and cannot distinguish different wavelengths of light, and we can only see gray scenes.