What is color measurement

Color measurement is the process of quantifying and recording the color properties of an object through specific tools or methods . The purpose of color measurement is to provide data support for color standardization, quality control and color management of different products to ensure consistent visual effects and color reproduction. Since color is generated by the reflection or transmission characteristics of light, color measurement is usually achieved through color detection instruments such as colorimeter , spectrophotometer and other professional equipment to capture the performance of color under different light sources or angles, in order to obtain more precise measurements.

Color measurement and detection instruments convert visual perception of color into digital signals, and analyze and quantify them through mathematical models and color space. The purpose is to eliminate subjective differences and provide a unified color standard for different batches of products.

Basic Methods of Color Measurement

There are three common color measurement methods: visual method, photoelectric integration method and spectrophotometry. The following introduces the principles and basic concepts of these three color measurement methods.

1. Visual method

Definition: The visual method is to directly observe the color with the human eye and compare it with the reference sample to judge the color difference. This method usually relies on the visual perception of the human eye, so errors may occur due to differences in observers, ambient lighting and color samples.

Advantages and disadvantages: The visual method is simple and intuitive and does not require complex instruments, but it is highly subjective, has limited accuracy, and is easily affected by lighting, observation angle, and the observer's personal visual differences.

Application scenarios: The visual method is mostly used for color inspections that do not require high precision, or as a preliminary color judgment method.

2. Photoelectric integration method

Definition: The photoelectric integration method uses a photoelectric sensor to measure color by capturing the intensity of light reflection or transmission. Commonly used instruments include colorimeter, etc., which convert color information through photoelectric signals.

Principle: The photoelectric integration method usually uses three stimulus value filters to detect color signals by simulating the three-color vision characteristics of the human eye (red, green, and blue), and calculates color parameters based on the color space model.

Advantages and disadvantages: Compared with the visual method, the photoelectric integration method provides more quantitative color measurement data and has better repeatability , but its accuracy may not be as good as the spectrophotometry method, and it is difficult to obtain more subtle color changes.

Application scenarios: Widely used in color control in printing, textile, plastic, coating and other industries, suitable for routine measurement of color consistency and color difference.

3. Spectrophotometry

Definition: Spectrophotometry uses a spectrophotometer to decompose light by wavelength and measure the light reflection or transmission intensity at each wavelength to obtain color spectral data.

Principle: Spectrophotometry analyzes the color performance in the entire visible spectrum according to the reflection, transmission or absorption of light of different wavelengths on objects, thereby accurately describing the color.

Advantages and disadvantages: Spectrophotometry is highly accurate and can reflect the spectral characteristics of color in detail, so it is very suitable for color measurement with high precision requirements. However, its equipment is complex, the cost is high, and it also has high requirements for the operating environment.

Application scenarios: Widely used in scientific research, laboratory analysis and industrial fields with extremely high requirements for color accuracy, such as coatings, cosmetics, food and other industries, for color formula design and quality control.

What are the color measurement instruments?

Color measurement devices fall into two broad categories: colorimeters and spectrophotometers.

Colorimeter:

A colorimeter provides quick color assessment by measuring the difference between a color and a standard color. It uses three photoelectric sensors to mimic the visual perception of the human eye and is often used for quality control.

Spectrophotometer:

Spectrophotometers provide more accurate color measurement data by performing a detailed analysis of the entire light spectrum. They measure the reflectance and transmittance of an object at different wavelengths, resulting in more accurate color values.

The Difference Between a Colorimeter and a Spectrophotometer

Features of colorimeter:

Easy to operate

Lower price

Fast measurement speed

Suitable for basic color matching tasks

Features of spectrophotometer:

Higher accuracy

Ability to analyze the entire spectral data

Suitable for complex color analysis

Suitable for R&D and high-precision scenarios

For more specific differences, please refer to the difference between colorimeter and spectrophotometer 

Common standard procedures for color measurement

Color measurement usually follows the relevant standards of the International Organization for Standardization (ISO) or the International Commission on Illumination (CIE), such as the CIELAB color space and the CIE XYZ color space. In addition, common color systems also include the Munsell color system, which is used to evaluate the ΔE calculation method for color difference. The specific measurement method depends on the industry and specific needs of the application. The following is a general standard measurement process:

1. Choose a suitable standard light source: Make sure the color temperature of the light source meets the measurement requirements.

2. Calibrate the instrument: Use a standard white or black board to calibrate the instrument to ensure the accuracy of the measurement results.

3. To take a measurement: Place the sample under the measuring instrument and select the appropriate measurement mode (reflection or transmission).

4. Analyze data: Use professional software to analyze measurement results and generate color reports.

Types and definitions of color spaces

Color space is a mathematical model used to quantify color in color measurement. It provides a structured way to represent color. Different color spaces have different uses and application scenarios. The following are commonly used color spaces:

RGB color space

The RGB color space is widely used in display devices such as computer monitors, mobile phone screens, etc. It forms other colors by combining the three primary colors of red, green, and blue.

CMYK color space

The CMYK color space is mainly used in printing, and it achieves color reproduction by mixing cyan, magenta, yellow and black.

CIE Lab *​ Color Space

A color space defined by the International Commission on Illumination (CIE) and widely used in industry for color measurement and analysis.

Color Measurement Applications

Color measurement is widely used in many industries, involving color management and quality control from raw materials to finished products. The following are the main application industries and measurement objects:

1. Printing and packaging industry

Color measurement objects: ink, paper, packaging materials, etc.

Application requirements: Ensure the accuracy and consistency of printed and packaged colors, especially in multi-batch production, where strict color matching is required to avoid color difference.

2. Textile and clothing industry

Color measurement objects: textiles, dyes, garments, etc.

Application requirements: The color of textiles is greatly affected by factors such as dyes and light. Color measurement helps maintain color uniformity and consistency during dyeing and printing processes, ensuring that the color of finished garments meets design standards.

3. Coatings and paint industry

Color measurement objects: pigments, coatings, paints, etc.

Application requirements: Used for coating color management on the surface of products such as buildings, automobiles, and home appliances. Color measurement helps with formulation design, ensures color consistency, and avoids color differences between batches.

4. Plastic and rubber industry

Color measurement objects: plastic particles, molded plastic parts, rubber products, etc.

Application requirements: Plastic products are prone to color differences due to material and temperature changes during production. Color measurement is used for color control in the production process to ensure that the color of the finished product is consistent with the design requirements.

5. Cosmetics and personal care industry

Color measurement objects: foundation, lipstick, eye shadow, hair dye and other cosmetics.

Application requirements: Cosmetic colors need to be precise and consistent, especially color control between different batches to ensure consumers' expectations of product colors. Color measurement helps manage the color consistency of different materials.

6. Food and Beverage Industry

Color measurement objects: chocolate, beverages, condiments, fruits and vegetables, etc.

Application requirements: Color measurement helps control the appearance of food and beverages and meet consumers' expectations for color; for example, the color of juice and the uniformity of chocolate affect consumers' sensory experience.

7. Automobile and transportation industry

Color measurement objects: car paint, interior materials, dashboards, seats, etc.

Application requirements: The consistency of the color of the car's exterior and interior is crucial to the brand image. Color measurement plays an important role in the color control of materials such as body paint, plastic parts, fabrics, and leather, ensuring the harmony and consistency of the colors inside and outside the car.

8. Electronic display industry

Color measurement objects: monitors, mobile phone screens, TV screens, etc.

Application requirements: Display devices require high-precision color performance. Color measurement helps calibrate display devices to ensure accurate color reproduction and consistent colors displayed between different devices.

9. Construction and decoration materials industry

Color measurement objects: tiles, wallpapers, carpets, stones, etc.

Application requirements: The color consistency of building materials is very important for the decorative effect. Color measurement ensures the color consistency of different batches of materials and improves the overall harmony of the decorative effect.

10. Scientific research and laboratories

Color measurement objects: various materials and samples.

Application requirements: In color science research, it is necessary to accurately measure the color characteristics of various substances. Color measurement is crucial in color experiments and color model verification.

Color measurement is widely used in these industries, providing technical support for color standardization, quality control and brand image, ensuring that the final product meets the high standards of the market and consumers' expectations.

Common Color Measurement Errors and Solutions

Cause of error:

Unstable light source

The instrument is not calibrated

Ambient light interference

Solution:

Calibrate instruments regularly

Use standard light sources

Avoid interference from external light sources