In the natural world, blue rocks from which objects can be fashioned are rare - a few marbles, lapis-lazuli and related rocks, and minerals containing copper. However those which, once ground, can be used as pigments are exceptional. Only lapis-lazuli and azurite come to mind. The long absence of blues from the palettes of our distant ancestors is therefore easy to explain as is the fact that blue pigments have always been an expensive commodity which became the objects of a very lucrative trade, spanning continents and oceans.

The primary goal of this book is to show how much ingenuity man has needed to employ in order to make blue materials. From Egyptian blue to copper phtalocyanine, ranging through Maya and Han blues, smalt, blue ashes, Prussian blue and artificial ultramarine, we cannot help but be in awe of the variety of technical solutions found. Each civilization has produced its own solution, or sequence of solutions. Thus one can say that blue pigments can be considered as markers of civilizations.