A spectral sensitivity in the human eye peaks at approximately 555nm, which means that green color appears to be more brighter when compared to other colors. At 490nm wavelength range, the sensitivity is just 20% in contrast to the sensitivity at 555nm range.
Figure 1. Color measurement
Moreover, the human eye can only differentiate approximately 10 million different colors, which is in fact very limited relative to the requirements of color measurement applications. Spectrometers are specifically designed to measure the actual wavelengths, and are hence perfect for color measurements. Visible light has a 390-750nm wavelength range. Therefore, color measurement systems are configured to cover from 380 to 780nm range with around 5nm (FWHM) spectral resolution.
Reflective Color Measurement
In order to facilitate reflective color measurements, an integrating sphere or reflection probe is usually needed. In either case, a white continuous light source lights up the surface to be measured. Additionally, a white reflective standard tile is required for calibration.
Figure 2. Avantes custom probes
Applications of Color Measurement
Color measurements can be applied to a wide range of industrial applications, such as color of paper, textile, paper, wine, fruit, and bird feathers. Avantes has designed a wide range of customized probes (Figure 2) to address the particular needs of the color measurement application. Color measurements are tipsily manifested in the L*a*b* color model, which comprises parameters for hue and brightness.
Avantes offers a range of spectrometers and custom probes that are designed to measure the exact wavelengths and prove suitable for color measurements.
This information has been sourced, reviewed and adapted from materials provided by Avantes BV.
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