Phosphorus, Tungsten, and Molybdenum – from Brilliant to Fanal®: Unusual Precipitation Methods of Triphenylmethane Dyes in the Early Twentieth Century

Triphenylmethane based dyes became popular after their invention in 1858 due to their brilliant shades and high tinting strengths and were used not only as colourants for textile and paper dyeing, but also as pigments in artists' materials under the commercial name ‘Fanal®’. However, the extent of their use as pigments in artists’ paints has thus far remained unknown. Despite their bright colours, the characteristic low lightfastness of their dyes and pigments inspired further research for new precipitation methods to increase lightfastness, which ultimately resulted in precipitation using complex salts of phosphorus, tungsten, and molybdenum. The present study is based on archival source research from I.G. Farben, the former producer of Fanal®, and Royal Talens, an artists’ paint manufacturer that used these pigments. This research focuses on the history of developments in precipitation methodologies employed for early triphenylmethane dyes and the development of the various lines of Fanal® pigments in oil paints produced by the Dutch manufacturer Talens in the late 1920s and onwards. Historic literature sources, such as the Talens publication Kunstschildersmaterialen en Schildertechniek by Frits Kerdijk that document the application of Fanal® pigments, are also highlighted.