The meaning of halo

Halo refers to a halo with blurred edges.

Introduction to halo:

The virtual shadow diffused from the edge of the developed image refers to that when strong light is projected on the film during exposure shooting, it is reflected to the surface of the film base through the film emulsion, thus causing the image to be blurred.

Photographic terminology:

Halo refers to the process of exposure shooting, when strong light is projected on the film, it is reflected to the surface of the film base through the film emulsion, thus causing image blur. In order to prevent this phenomenon, sometimes a colored layer is coated between the film base and the emulsion layer, which can be removed during development, or a gray layer is coated on the film base, which is called an anti-blooming layer.

Introduction to light:

Light is a physical term, and its essence is photon flow in a specific frequency band. The light source emits light because the electrons in the light source gain extra energy. If the energy is not enough to make it jump into outer orbit, the electron will accelerate.

And release energy in the form of waves. If the transition just fills the vacancy in the orbit and reaches the stable state from the excited state, the electron will stop the transition. Otherwise, the electrons will jump back to the previous orbit again and release energy in the form of waves.

The research history of light, like mechanics, was paid attention to in ancient Greece, and the law of light reflection was widely known as early as Euclid's time. However, before the separation of natural science and religion, human understanding of the nature of light hardly improved, only staying at the level of formal understanding of the spread and application of light.

In addition, history tells us that Mozi, the founder of the ancient Mohist school in China, discovered the law of light reflection and established the optical system of China. In the17th century, there were two voices on this issue: wave theory and particle theory.

But the meaning of wave here is not mechanical waves like sound waves and water waves, but statistical waves, that is to say, the behavior of a large number of photons reflects the nature of waves. At the same time, light has dynamic mass, and its mass can be calculated according to Einstein's mass-energy equation.