Los secretos del azul de esmalte: Quaderni di fornace

Abstract

Blue smalt has a long history as an artistic pigment despite the stability problems associated with its use. Born as a colorant for the glass industry, many artists became aware of its versatility, making a leap to the pictorial palette at the beginning of the Renaissance. The main objective of this work has been to identify, interpret and compare the various recipes from European written sources, and especially from the so-called Quaderni di fornace, which describe the preparation of the so-called enamel blue suitable for painters, also collected under the term painters' blue, in order to trace the evolution of this pictorial material over the centuries. For this, the different varieties of this pigment that could be found on the market have been analyzed, both those intended for the glass industry and for artistic purposes. The detailed study of the processes of obtaining, synthesis and compositional variations of the blue enamel pigment described in these sources has made it possible to verify the existence of numerous variants in the formulas for its manufacture, intended to provide not only different shades, but also different qualities depending on the use for which it was intended, even within the same variety, as in the case of painters' blue.