New primary standard for specular gloss measurements

A new primary specular gloss standard has been developed at the National Institute of Standards and Technology to overcome the disadvantages of black glass. This new standard is a high-purity BaK50 glass with good mechanical durability and homogeneity. In addition, the index of refraction nD=1.5677 is close to the value specified for the theoretical standard, and the dispersion characteristics are similar to black...