Tracey Chaplin & Nicholas Eastaugh 
Pigment Compendium [PDF ebook] 

This is an essential purchase for all painting conservators and conservation scientists dealing with paintings and painted objects. It provides the first definitive manual dedicated to optical microscopy of historical pigments.
Illustrated throughout with full colour images reproduced to the highest possible quality, this book is based on years of painstaking research into the visual and optical properties of pigments.
Now combined with the Pigment Dictionary, the most thorough reference to pigment names and synonyms avaiable, the Pigment Compendium is a major addition to the study and understanding of historic pigments.