For diffuse reflection measurements, the WS-2 reference tile is ideal. For specular reflection measurements, the RS-2 is available.
The WS-2 reference tile is made out of a white diffuse PTFE based material, which is considered the highest grade reference material for diffuse reflectance. It is mostly used in colourimetric applications where a reference signal has to be obtained during a reflection measurement.
The PTFE material is high purity and processed using exacting standards to an amorphous structure, so the tile reflects light from 350-1800nm at circa 98% and from 250-2500nm at more than 92%. The material offers long term stability, even in UV applications. The plastic is hydrophobic and chemically inert, so can be cleaned.
For gemmology applications, the WS-2 is used in combination with a reflection integrating sphere. The gemstone is put on the middle of the tile with the integrating sphere over it.
The special WS-2-GEM is designed to facilitate holding and cooling a gemstone with liquid nitrogen, as it features a cavity and hole in the middle of the tile.
The RS-2 is a mirror tile which can be used as a reference standard for specular reflection measurements.
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