The principle of determining the chromaticity of petroleum products is to use colorimetric method to compare the color depth of the sample to be tested with the standard color plate, and determine the degree of color depth of petroleum products by comparing the chromaticity values.
The specific measurement process is as follows: place the sample to be tested and the standard color plate on the colorimeter, irradiate the lighting source on the standard color plate to generate standard brightness light on its surface. At the same time, the reflected light of the sample to be tested can also shine on the colorimeter after passing through a specific optical path. The colorimeter detects the spectral characteristics of the reflected light generated by the standard color plate and the test sample through optical sensors, and then calculates the color difference between the two, thereby obtaining the chromaticity value of the test sample, reflecting the color depth of the sample.
Usually, the results of the colorimetric determination of petroleum products are expressed in the international standard unit - colorimetric value (Pt Co). The higher the chromaticity value, the darker the color of the petroleum product. On the contrary, the lower the chromaticity value, the lighter the color of the petroleum product.
