* It consists of a light source, an optical system, a detection system, a data processing and display system. The whiteness calculation of this instrument is blue light whiteness R457. * The whiteness value of an suace with a diffuse reflectance ratio of 1 in the visible spectrum range is defined as 100, and the whiteness of a black suace with a spectral reflection factor of 0 is 0. * High-quality imported components are used, and the reliability is good. * Reasonable and concise optical path design, using a corrected color filter system, can quantitatively reflect the whiteness value after fluorescent whitening. * No need to preheat after turning on the machine, and it can be measured after simple calibration, which is easy to operate.