This standard specifies a method for measuring the dispersion light transmitance of carbon black water using a VisibleSpectrophotometer, which is applicable to coated superhydrated dispersed carbon black. This method reflects the dispersion characteristics of carbon black by measuring the light transmittance of carbon black in water dispersion systems. In a spectrophotometer, when a directional ray of light passes through carbon black water dispersion, a part of the light is reflected, scattered or absorbed, and only a part of the light can be transmitted. This light transmitance value is used to quantify the dispersion performance of carbon black. The standard also lists the required reagents and instruments, including analytical balance, oven, spectrophotometer, etc., to ensure the accuracy of the test.