Practical application of CS-580 spectrophotometer on painted metal parts
Painted metal parts are important parts and play a very important role in the products of various industries. In the process of metal painting, due to materials, equipment tools, environment and other reasons, painted metal parts (pictured 1) The finished product will produce chromatic aberration. For high-demand enterprises, it is necessary to abandon the method of visually discriminating chromatic aberration in the past, and instead seek accurate measurement methods to monitor the quality of painted metal parts.
the color difference formula is used to evaluate the color difference of painted metal parts. : the color difference formula was proposed by FJJClark, R. McDonald and B. Rigg in 1984 based on the modification of the JPC79 formula. It overcomes the deviation between the calculated value of the JPC79 neutral color region and the visual evaluation result. Large defects, and further introduced the brightness weight factor and the chroma weight factor to meet the needs of different applications. This formula is recommended by the Color Measurement Committee (CMC) of the Society of Dyers and Colourists, and its color difference expression is
In the formula
、
and
are the chromaticity parameters of the standard color samples, and the values in the above formula
、
、
. They are all calculated by the CIELAB color difference formula; the brightness weighting factor and the chroma weighting factor are used to adjust the degree of influence of brightness and chroma on the total color difference, so different ratios should be taken in different applications. A large number of experiments have shown that it is recommended to use the perceptible parity of chromatic aberration.
，For example, the CMC (1:1) formula is generally used for color correction of digital systems and industries such as paints or plastics. For color acceptability evaluation, it is recommended to use
，For example, the quality control of products in the textile industry mostly adopts the CMC (2:1) formula.
Since the CMC color difference formula has better visual consistency than the CIELAB formula, the quality control of different color products can use the “single number tolerence” independent of the color area of the sample to provide color measurement to the user. Instrument evaluation with color difference brings great convenience. Therefore, the color difference formula has been widely used since its introduction. Many countries and organizations have adopted this formula instead of the CIELAB formula, so this formula will be widely used in the industry as a general and authoritative color difference formula.
The color spectrum measuring instrument is the first color measuring technology platform color measuring instrument in China. It integrates a number of technical features and extends the boundary of color quality control in production. The built-in color difference formula includes CMC (1:1). Formula and CMC (2:1) formula, therefore, can meet the color difference measurement requirements of painted metal parts, can accurately measure the color difference of painted metal parts, and obtain the color difference data tested according to different formulas.
Here’s how to use the Spectrophotometer CS-580 of Color Spectrum to test the color difference of painted metal parts.
The first step: open the instrument, set the parameters and formulas according to the instructions, and perform black and white calibration (Figure 3 and Figure 4);
