The surface gloss of an object is closely related to the roughness of the object surface [1-2]. When light strikes the surface of an object, part of the light will be absorbed, part of it will be reflected or scattered, and part of it will be refracted. The smaller the roughness of the object surface, the more light is reflected and the higher the gloss. On the contrary, if the surface of the object is uneven, the scattered light will increase, resulting in a decrease in gloss.

The human eye's perception of the roughness of an object's surface is limited. Using micro-surface theory knowledge, you can calculate according to the formula:

h = λ / cosα
Where: λ is the wavelength of the incident light; α is the angle of incidence; h is the roughness.

Assuming an incident angle of 60 °, h = 1.1 μm can be calculated according to the formula, that is, when the surface roughness h of the object is greater than 1.1 μm, the human eye can observe the unevenness of the object, and the gloss is reduced.