Four-level color refers to the color difference of the same batch of products or the color difference with the confirmed samples is not less than 3-4 levels, that is to say, the colors cannot be too different. The specific size is not less than grade 3-4. The so-called level 3-4, the state has specific provisions.

This standard is equivalent to the international standard ISO 105/A03- 1993 ((Textiles-color fastness test-gray sample card for evaluating staining)).

People who choose orange usually love nature very much and are eager to blend in with nature. They like outdoor activities. Walking in the forest will make them feel the power of rebirth. If orange lovers are forced to stay in their rooms for a long time, they may get sick.

Brown represents stability and neutrality. Brown is also the color of Mother Earth, which embodies the truth and harmony widely existing in nature. Brown is a stable and protective color, representing vitality and emotion. In the test of color pyramid, brown is considered as a color with mental resistance.