In the section “Prof. Theo de Beer about ….” we share with you articles from the unpublished book of Professor Theo de Beer “Everything about art materials”. Prof. Theo de Beer managed the Old Holland company from 1982 till 2000 and made a huge contribution to its development.
The crushed lignite was used for the first time by artists in 1580 as a pigment to make oil paint. The decayed plants have decomposed into acid lignite. The finest parts of the layers of lignite that still contain humic acids and cellulose are used for making the pigment. The first mines were opened near the German city of Kassel and later near Cologne, after which these two nut-brown colours are named. The Flemish artist Anthony Van Dyck (1599-1641) used the colour a great deal, hence its name. He loved the paint so much because it had a transparent warm reddish undertone. Cologne earth has a deeper and redder colour than Cassel earth. Around 1980, the non-lightfast pigment was replaced by lightfast transparent iron oxide pigments, which are sometimes mixed with a little black. This makes the paint slightly less transparent. Lignite is P. Br. 8.
Van Dyck brown, or Cologne and Cassel earth, have little colour strength and are not lightfast. The pigment was also unsuitable for use on alkaline surfaces. The non acid-fast pigment has a high oil demand, making it transparent. The glazing product that significantly delays the drying process provides a soft layer of oil paint. The colour is now made up by mixing lightfast pigments with each other, which have transparent properties.