SUMACH GALLNUT EXTRACT is a natural extract prepared from the Chinese sumach gallnut (Rhus semialata Murr.). This gallnut extract was especially developped for textile and natural dyeing uses : a very high content in tannic acid combined with a very low colour.
Main constituents : Hydrolysables tannins > 95 %.
Yellowish powder in granular form producing almost no dust during handling. Very good solubility in cold or hot water.
Pre-treatment of vegetable fibers : The high tannic acid content of this gallnut extract is perfect for the pre-treatment of cellulosic fibres (named engallage in this case) to improve the fixation of mordant during the mordanting step.
THIS TANNIN HAS A VERY LOW COLOUR. RECOMMEND FOR ENGALLAGE STEPS.
Natural dyeing and printing textile : any fiber can be dyed with oak gallnuts. It does increase lightfasntess of the resulting colours. In presence of iron sulphate, this extract forms very solid and very dark complexes. This property allows to use the extract of gallnut for shading (with iron sulphate) after dark shades (madder, indigo) on silk and wool. This makes these shades even darker while limiting the iron sulphate (which makes these fibers weak).
Other uses : tannery, manufacture of iron gall inks.
The plant :
The Chinese sumach is a shrub of 2 to 10 m tall. It is common of the Northeastern India, in China, Japan, Korea and Indonesia. Galls are caused by the sting of an insect on leaves or petioles. The gallnuts of Sumach are very rich in hydrolysables tannins (tannic acid).