The color type of nephrite (Wada jade) has a great influence on its economic value, especially white jade. Therefore, accurate color division is very important in the process of jade identification, identification and classification. The following aspects should be noted in the identification and trade practice: 1. Light source: The nephrite will have different color tones under different light sources. The different colors of nephrite will behave differently under the same light. The ancients Zeng Yun "do not look at jade under the lamp". It is best to use natural light when distinguishing the classification. In case of strong sunlight, avoid direct sunlight. The auxiliary light source is an ordinary fluorescent lamp with a color temperature of 5000-7000K. 2. Environment and background: The environment has a significant influence on the identification of colors. The laboratory should use neutral white and gray as the ambient color, and the samples to be compared and compared should be placed on large white cloth, cloth paper or white paper for identification colorimetry. The backing material requires weak fluorescence and is flat and resistant to dirt. It is also not necessary to have strong reflections. Different workbenches in the same laboratory must be fixed to the same backing for a long time as a colorimetric background. 3. The thickness factor of the sample: the thin sample will appear lighter in color and the thicker sample will appear darker in color. Therefore, the general laboratory specifies that the colorimetric part is between 5 and 8 mm thick. Insufficient or excessive parts should be technically measured to determine the depth of the color. 4. Establish colorimetric standard sample and reference sample library: According to practical experience, two or three of light blue, gray white and yellow green color should be selected respectively, and colorimetric standard samples should be established to ensure the white color of jade white jade/white jade color. Stability; establish a boundary line between topaz and white jade to ensure the stability of the classification of topaz. Other color categories should be referenced to the sample library so that staff can often compare references in actual work. 5. Inspectors: The identification of colors should be performed by inspectors who have experienced systematic training. Inspectors should be familiar with and understand industry traditions. It is difficult for untrained personnel to identify small differences in color, nor to take into account some of the precautions and industry traditions of identifying classifications, which can cause large errors in approaching classification boundaries and concepts. 6. Other precautions: When comparing colors, pay attention to the different degrees of sensitivity of different people's eyes to gray, yellow, light blue and other colors. The comparison test shows that different people have color parallax, color blindness and color weakness; pay attention to morning, noon, afternoon. The natural light color temperature is different at different times; pay attention to the position, front and back, and direction of the sample; pay attention to the effect of sample transparency on the color; pay attention to the effect of color on the sample on the color, sugar, and other colors. Strench Metallic Jersey Fabric In Knit Brushed Terry,Metallic Jersey Fabric,Poly Rayon Terry Knit,Poly Cotton Indigo Fleece Terry Shaoxing Jiuyang Textile co.,ltd , https://www.textilejy.com