Extract from the sorghum plant, belonging to the graminaceae family
Extract from the sorghum plant, belonging to the graminaceae family, and the different varieties produce colours ranging from dark red and brown to light yellow and white. In China sorghum extract was used traditionally as a red fabric dye, but new extraction methods now make it possible to obtain a uniform quality that allows the use of these dyestuffs in other fields.
OLD WOOD uses the variety whose main colouring agents are pelargonidin, petunidin, cyanidin, all of them anthocyanidin compounds and more specifically isoxanthoketone galactosides.
The pigment, which artists call “Rose Madder”, was first isolated by in 1826 by the chemists Colin and Robiquet, who found it to be based on hydroxyanthraquinones, the two colouring agents in Rubia tinctorum extracts, which were permanent alizarin and purpurine.
Pelargonidin produces a reddish orange, while cyanidin delivers a magenta hue and petunidin bluish shades. Accordingly, with Venetian Red OLD WOOD has created a pigment paste that produced a dark red brownish colour with great transparency and depth, and above all a silky warmth.