How to establish color standards, improve product appearance, color quality control, and then conduct computer color matching? Here we have to mention a color detection tool – Color Detector.
Currently, there are many types, brands, and vendors of colorimetry instruments. Some customers are unfamiliar with color measurement. Faced with such a wide variety of instruments, there can be significant price differences and varying measurement results. Why are some called colorimeters and others called spectrophotometers? What are the differences between these instruments? What are their uses?
Below we will introduce in detail:
What is a “colorimeter” and what is a “spectrophotometer”
As the name suggests, a “colorimeter” is used to measure the color difference between two samples. Its accuracy is relatively low, and it generally cannot accurately determine the absolute values of a color’s color coordinate space (L, a, and b values). However, it can determine the color difference (ΔE) between two samples (usually between a standard and a sample). This colorimeter does not provide absolute color data, cannot exchange data with others, and cannot establish and manage its own color standards database.
- Colorimeter
The spectrophotometer offers high accuracy and uses pre-positioned plates, eliminating the need for standard black and white plates used in the calibration process of traditional colorimeters and spectrophotometers. The built-in software is powerful and contains all the necessary color equations, standard light sources for different tasks, and a large number of industry-specific and application-specific indicators.
Spectrophotometer
Handheld Colorimeter
- Spectrophotometer
- Design principles
Spectrophotometers are designed according to the spectrophotometric principle, while standard colorimeters are designed according to the tristimulus principle. Colorimeters offer high precision and increasing versatility. A color spectrophotometer can simultaneously measure both specular reflection (SCI), a measurement method that includes specular reflection, thereby reducing the influence of the sample surface and making it particularly suitable for color quality monitoring and computer color schemes, and specular reflection excluding specular reflection. This type of measurement produces results similar to those observed by the naked eye. Because it measures reflectance at each wavelength, it is suitable for complex color analysis, though this comes at a relatively high price. Tristimulus colorimeters are relatively inexpensive, compact, flexible, and easy to operate.
- Measurement principle
A colorimeter automatically compares the color difference between a sample and the product being tested, outputting three sets of data: CIE L, a, and b, as well as ΔE, ΔL, Δa, and Δb. Unlike pure colorimeter methods of color measurement, spectrophotometers can measure the “reflectance curve” for each color point (at 10nm or 20nm wavelength intervals), but colorimeters cannot. Spectrophotometers can simulate multiple light sources, while colorimeters typically only have one or two.
- Light source
In color measurement instruments, the selection of light sources should first consider the stability of the obtained spectral curve, the direction of the light source, the lifespan and effectiveness. Currently, the two light sources used are mostly LED lamps and xenon lamps.
Xenon lamps are generally used for UV light source measurements. They can produce short, high-intensity arcs, but they struggle to produce repetitive arcs of the same intensity. Furthermore, xenon lamps require a relatively complex high-voltage oscillation excitation circuit and are very complex to maintain. Replacing them requires replacing not only the bulb but also the entire capacitor set, making them more expensive.
Portable Spectrophotometer
Benchtop Spectrophotometer
What is the difference between a colorimeter and a spectrophotometer in application?
The use of LEDs in current standard color measurement instruments is both technically and economically appropriate. Portable instruments, in particular, need to be lightweight, energy-efficient, and easy to maintain and operate. Color spectral color measurement instruments use long-life CLEDs (full-band balanced LED light sources), eliminating the need to worry about frequent light source replacements.
Typically, a colorimeter is used to measure the color difference between samples. Spectrophotometers contain all the necessary color equations, standard light sources suitable for different tasks, and a large number of industry and application-specific indicators, making them particularly suitable for color quality monitoring and computer color control.
A spectrophotometer is an instrument commonly used for color detection and measurement. When using a spectrophotometer for color detection and measurement, certain measurement standards must be followed to ensure the accuracy and comparability of the measurement results.
The following are common spectrophotometer color detection and measurement standards:
- Color Difference Standard: Color difference refers to the degree of difference between two colors and is generally calculated using the international standard CIE color difference formula. When measuring color, the color difference between the sample to be measured and the standard sample must be compared to assess the difference between them.
- Light source standards: Commonly used light sources in spectrophotometers include standard light sources such as D65, D50, and A. The choice of light source should be based on the characteristics of the object to be measured and the operating environment to ensure the accuracy and comparability of the measurement results.
- Aperture Standard: Aperture refers to the size of the portion of the spectrophotometer that collects light. Different aperture sizes can significantly affect measurement results. Generally, the appropriate aperture should be selected based on the characteristics of the object being measured and the operating environment.
- Calibration Standards: Spectrophotometers require regular calibration to ensure accurate measurement results. Calibration includes zero-point calibration and spectral calibration, and must be performed according to the user manual.
- Data transmission standards: During the color measurement process, it is necessary to ensure the accuracy of the measurement results and the reliability of the data. Therefore, it is necessary to select appropriate measurement software and transmit data in accordance with the standardized data transmission format.
