General Introduction to Colorimeter

Colorimeter, also known as Chroma Meter or, is an instrument used to detect the color difference of a product. It calculates the color difference between two products by measuring their LAB values.

Overall design of Colorimeter system:
The Colorimeter mainly consists of a light source, a d/8 degree integrating sphere, a color sensor, spectral response curve correction, signal processing, and display components.

The light produced by the light source is used as the incident light to shoot onto the edge of the tested color. The tested color plate can be a standard color plate or a measured sample, and then the light is collected by the integrating sphere and fed to the color sensor.
Correct the spectral response curve of the color sensor output, calculate the color difference result, and display it on the LCD display screen.

The function of a Colorimeter:
Colorimeter, an instrument used to measure the color difference of products, is generally portable or handheld. The overall volume of a color difference meter is not large, and it can be directly used in industrial production processes to improve product quality. Although the measured values are not as accurate as those of a desktop color difference meter, the advantages are convenience, simplified functions, and affordable prices.

So Colorimeters are highly sought after in many industries, including food, paint, pharmaceuticals, plastics, printing, dyeing, clothing, automotive manufacturing, hardware, electronics, ink, coatings, textiles, and other color detection fields.

The analysis method and principle of Colorimeter:
Currently, in industry, the main method for measuring product color is to use the CIE Lab color space. The CIE Lab color space uses an L value to represent the brightness of the color, a value to represent the green red value of the color, and a value to represent the blue yellow value of the color.

After measuring the product, we will see a set of Lab values on the instrument screen, which are standard samples. If we measure the sample according to this standard sample, we will display a set of △ L, △ a, △ b, and △ E values on the screen, which are the color difference values between products. Generally, in production, the color deviation of the product is mainly determined by looking at this set of values.

Now, based on an example to illustrate the analysis process of a color difference meter, the customer first provides the manufacturer with a standard product Colorimeter measurement result with a Lab value of 80/27/35, and then the manufacturer starts measuring the sample values produced by themselves based on this set of values;

If the Lab value of the measurement result is 81/28/34, then the values of △ L, △ a, and △ b are+1/+1/-1, respectively. This indicates that the product’s L value is brighter than the standard, the a value is redder than the standard, and the b value is bluer than the standard. By comparing the Lab values of the product and the standard color sample, we can easily determine the current color status of the product.

In addition, by using two sets of Lab values, we can calculate the color difference between the two colors. If the color difference is greater than 1, our eyes can distinguish it.

Therefore, we can set a certain tolerance range in advance. During quality control, if the color difference between the measured sample and the standard color is within the tolerance range, the product is qualified. If it is beyond the tolerance range, the product is unqualified. By using the Lab color space, our production control has been data-driven.

Based on the various data results displayed by the Colorimeter after color measurement, the following analysis can be conducted:
△ E represents the total color difference, and the larger the value, the greater the color difference. The calculation formula △ E=[(△ L)+(△ a)+(△ b)] 1/2;
A general Colorimeter detects two sets of data, including L, A, and B values, and the difference between the three values is obtained through the following formula:
△ L=L sample – L standard (brightness difference),
△ a=a sample – a standard (red/green difference)
△ b=b sample – b standard (yellow/blue difference)

The meaning it represents is:
If Δ L is positive, it indicates a bias towards white; if Δ L is negative, it indicates a bias towards black
If Δ a is positive, it indicates redness; if Δ a is negative, it indicates greenness
If △ b is positive, it indicates a yellowish color, while if △ b is negative, it indicates a blue color

Application of Colorimeter in daily life:
1. Measurement of color adjustment in Colorimeters
When a customer receives a sample, they need to perfectly reproduce the same color as the sample, which requires repeated confirmation of the large sample. Early color management relied on comparing the difference between the small sample and the standard sample with the human eye, but this difference was not visible to the naked eye or very inconspicuous, so the process was handed over to the workshop for production.

This approach has too strong subjective consciousness, not everyone’s opinions and visual effects are the same, and is greatly influenced by external factors. So in modern color management, people use Colorimeters in conjunction with computer systems. The biggest advantage of using color difference meters to participate in color matching is that they can correct formulas based on the data provided by the Colorimeters, which can complete color matching tasks faster and more accurately.

2. The Role of Colorimeter in Quality Control
After the formula is determined and put into production, due to changes in many factors during production, color deviation may occur in batches of products. Therefore, it is necessary to frequently use a Colorimeter
to measure color deviation during production to adjust the production process and achieve product color consistency.

3. Volume transmission aspect
Nowadays, customers usually provide color cards or samples, so when signing contracts with users, they should try to save the physical objects as standards. Even high-end Colorimeters may have deviations according to the actual environment. The national color standards are based on standard whiteboards and color boards, rather than instruments.

Portable Colorimeter/Chroma Meter is an innovation color measuring tool with powerful configuration to make color measurement easier and more professional; It support Bluetooth to connect with Android and ISO devices, Portable Colorimeter/Chroma Meter will take you into a new world of color management; It can be widely used to measure color value, color difference value and find similar color from color cards for printing industry, paint industry, textile industry, etc.

Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.

Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator Guns, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.

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