Material Characterization

Reflection spectroscopy, often called reflectance spectroscopy, is often used to non-invasively and non-destructively characterise objects and materials. Comparing the reflected light to the light used for illumination, can tell you a lot about the characteristics and nature of the object or material being researched, for instance exact colors, compounds and more.

When light hits a surface of a material it will either be reflected, absorbed or transmitted through the material (or a combination of the above). The reflectance of this light will depend on the structure and the material properties of the object. 

Depending on the reflectance application, a wide variety of light sources, accessories, fiber-optic probes and spectrometers can be chosen, offering you a tailor-made solution for your specific application.

Color Measurements

Thanks to the reflectance of light, we humans are able to see color and to differentiate between objects. One of the most prevalent uses for reflectance spectroscopy is color measurement. Color measurements are used in a variety of industrial applications such as determining the color of textile, paper, fruit, wine, and bird feathers.

Spectrometers are designed to measure exact wavelengths, and are therefore ideal for color measurements. Visible light has a wavelength range of 390-750 nm, so generally color measurement systems are configured to cover the range from 380-780 nm with a spectral resolution of around 5 nm (FWHM).

To facilitate reflective color measurements a reflection probe or integrating sphere with halogen light source is typically required. In either case, a white continuous light source illuminates the surface to be measured and a white reflective standard tile is needed for calibration.

Avantes has developed a variety of custom reflection probes to meet the specific demands of different color measurement applications. Color measurements are manifested in the L*a*b* color model which includes parameters for brightness and hue. This and other presets for color measurements can be found in our AvaSoft color application software.

For standard color measurement applications, we have developed two different bundles: one for small areas and one for surfaces. Both bundles feature the AvaSpec-ULS2048CL-EVO spectrometer, but offer different light sources and accessories.

Configuring a Setup

Since reflection measurements can be performed in a fairly broad wavelength range, Avantes offers several spectrometers that are suited for reflection measurements in the broad range of 200 to 2500 nm. The most common option for reflection measurements is the AvaSpec-ULS2048CL-EVO, configured from the UV to the near-infrared range.

To broaden the range even further, multi-channel configurations can be used as well. This allows you to measure in a broad wavelength range while still maintining a high resolution and sensitivity.

Accessories for reflection measurements can range from integrating spheres to various reflection probes and collimating lenses, depending on the application. We also offer a reflection stage to easily measure small samples.

Application Examples

Below are some detailed application notes on various uses of reflection spectroscopy in different applications and industries.

These are some of the products mentioned above. To find the perfect setup for your specific application, contact one of our sales engineers for advice.

Why Avantes for your reflection application?

  • Multi-channel capabilities to measure broad wavelength ranges
  • Extensive knowledge on reflection and color measurements, setups, accessories and software
  • Wide selection of reflection probes for various purposes

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