Practical application of color reader

First: Measurement of color matching

When the user gets a sample, it needs to reproduce the same color as this sample. At this time, repeated proofing is required. In the past, the difference between the sample and the standard sample was compared by the human eye. When it is within the allowable range, the process is handed over to the workshop for production. Due to the subjective factors of the human eye, this difference is difficult to determine. At this time, a colorimeter can be used to measure the difference between the sample and the standard sample, and determine whether the color difference of the sample meets the range according to the difference. This can reduce the uncertainty of human eye observation

The biggest advantage of using a colorimeter to participate in color matching is that it can modify the formula according to the data provided by the colorimeter and refer to the color map, which can complete the task of color scheme faster and more accurately. Here is an example

If the color coordinates of the standard sample are

      L *= 74.40, a *= 1.67, b *= 23.80

  

Set the measured value of the standard sample as the standard, and then measure the sample to get the result of the sample

      L *= 74.39, a *= 0.67, b *= 20.30; dL *= 0.01, da *= 1.0, db *= 1.50


 It can be seen that the next time you correct the sample formula, you should add green (or reduce red) and blue (or reduce yellow). Specifically, you can determine the degree of addition according to the test results, and repeat it several times until the color difference is within the allowable range. Within the range, experienced users can basically determine the ratio of the formula between 2-3 times according to the value of the color difference count.




Second: the role of colorimeter in quality control

When the formula is determined and put into production, due to changes in many factors in production, the color deviation of the batch of products may occur. In this way, it is necessary to measure the color deviation with a colorimeter in production to adjust the production process to achieve the color of the product. consistency.  




Third: quantity transmission

         Today's customers generally provide color cards or samples, so that when signing a contract with the user, try to save the actual product as the standard. No matter how high-end the instrument is, there are also deviations according to the actual environment. The national color benchmarks are based on standard whiteboards and swatches. The benchmark is not based on the instrument. Common problems in the use of colorimeters

  

       1. A customer provides the manufacturer with a set of color coordinates, but does not provide standard samples. In this case, be sure to find out which color space the color coordinates provided by the customer are measured in, as well as lighting conditions, light source types, and different colors. In the coordinate space, the measured values are very different, and there is no comparability. In the same color space, the lighting conditions are different, and the color coordinates are also relatively different, but the color difference is relatively small. 

 

       Suggestion: Let customers provide standard samples, use standard samples to transmit to users, use standard samples as benchmarks, and control color difference

         2. The above examples are all the standard space of CIE1976. The color coordinate space of the current instrument must be determined according to the user's color coordinate space

  

       3. All instruments, including spectroscopic colorimeters, use the standard whiteboard as the benchmark to adjust the instrument. When the instrument is used for a period of time, the standard whiteboard with random tape must be used to re-calibrate the instrument to achieve higher measurement accuracy.


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