Robuta

https://www.spectroscopyasia.com/technique/term/reflectance-standards Reflectance Standards | Spectroscopy Europe/World reflectance standardsspectroscopyeuropeworld https://nrc-publications.canada.ca/fra/voir/objet/?id=6fb2d517-93c9-49e3-9310-0c142c272701 Investigation of photoluminescent effect in opal glasses used as diffuse reflectance standards -... Investigation of photoluminescent effect in opal glasses used as diffuse reflectance standards