First, it is necessary to distinguish between "colorimeter" and "spectrophotometer"
Color difference scores are color filter (tristimulus value) colorimeter and spectrophotometer colorimeter. By imitating the feeling of human eyes, the tristimulus values are converted into XYZ or Lab tristimulus values. Because it is difficult to get a color filter with good reproducibility, the consistency between instruments is very poor, and it belongs to an entry-level instrument.
Spectrophotometer is generally equipped with integrating sphere and grating, and its structure is relatively complicated. This instrument can detect the color difference and monochrome problems of two products by detecting the color.
The spectral colorimeter converts the ratio of the reflection spectrum of the sample to the incident spectrum of the irradiated sample-the reflectivity of the sample into a chromaticity tristimulus value corresponding to the visual perception of the standard observation human eye through a microcomputer in the instrument according to the chromaticity mathematical model. Spectral colorimeter is suitable for any application, can simulate all standard light sources specified by CIE, can give spectral data and metamerism index, has very good repeatability and reproducibility, conforms to international general technical standards, and is the most commonly used technology today.
However, the price of this instrument is relatively high, but the measurement accuracy and analysis strength will be much better than that of the color difference meter.
Second, the color difference accuracy requirements
You need to know which color difference instrument is suitable for your industry. Each industry has different requirements for color difference accuracy, that is, △Eab. If △Eab is between 0- 1, then you must choose a more accurate instrument. These are generally rubber and plastics, coatings and paint industries; If high precision is not required, you can also choose a general colorimeter.
Third, we should distinguish between "0/45 degree" and "d/8 degree integrating sphere"
The common optical structures are also the two most widely used in the market at present, no matter the colorimeter or spectrophotometer test: one is "0/45 degree" and the other is "d/8 degree integrating sphere".
"0/45 degree"
"0/45 degree" is the structure closest to the angle of human eyes to observe things, so the color information measured from this angle is the closest to the observation result of human eyes. 0/45 degree can only be used to measure smooth surfaces and cannot be used for computer color matching.
8-degree integrating sphere "
"d/8 degree integrating sphere" is the most commonly used structure for object color detection, and the measured data is relatively stable. It can be used for measuring various surfaces and computer color matching.
Fourth, the difference between different light sources.
In the color measuring instrument, when choosing a light source, the first consideration should be the stability, directionality, life span of the light source and the effectiveness of the final spectral curve. CIE specifies the spectral specificity of several different types of typical light sources.
1.D65: Measure the sample irradiated by sunlight (including ultraviolet radiation) with normal sunlight (including ultraviolet wavelength region) with correlated color temperature of 6504K.
2.c: Normal sunlight with a correlated color temperature of 6774K (excluding ultraviolet wavelength region) is used to measure the samples irradiated by sunlight in the visible wavelength region (excluding ultraviolet radiation).
3. Answer: Incandescent light with a correlated color temperature of 2856K is used to measure the sample irradiated by incandescent light.
Five, combined with the operation performance of the instrument
In addition, attention should be paid to the simplicity of instrument operation when selecting instruments, and the complexity of instrument operation should be determined according to user groups.
At present, most portable hand-held color difference meters are humanized and easy to operate, which basically belongs to one-button measurement and rapid analysis. However, some old color difference meters with many functions are complicated to operate and may need professional training to master.
Complementarity of intransitive verb products
In addition to providing different series of color meters, color meter manufacturers will also provide a variety of supporting products, such as quality control software, color database management module, customer management module, color standard data management module and so on. Hardware, there are attachments * * * for special sample measurement. These supporting products can make the function of color measuring instrument in quality inspection, management and production more perfect. Even if some functions are not needed at present, in the long run, once the system is upgraded, only supporting products need to be added, which is not limited by the color difference meter itself.
For example, if you use the color matching software of Sanenchi first, then you choose the color difference meter of Sanenchi. Similarly, whether you choose Minolta or Lido in Elsa, it is a complete set. So far, I haven't heard that software instruments between different brands can be universal.
Seven, product appearance
At present, the test aperture of the general color difference meter is 4mm or 8 mm. If your product is curved or small in size, you need to consider the test aperture. For example:
LAV):2.54 (1 inch)
Medium aperture (MAV): 1.5 cm (0.6 in).
Small aperture (SAV): 0.75cm x1.0cm (0.3in x 0.4).
Ultra-small aperture (VSAV): 0.3cm x 0.8 inch (0. 12 inch x 0.3 1 inch)
Eight, whether there is a national measurement certification.
The chromatic aberration meter is a measuring instrument, so you need to know whether the product can meet the national measurement requirements, otherwise there will be disputes and your data can't be referenced.