A natural green dye obtained from the powdered bark of the buckthorn bushes (Rhamnus globosa, Rhamnus chlorophorus, and Rhamnus utilis) that are native to China and Russia. The dye is extracted from the leaves, roots and bark with an alkaline solution. Lokao was a popular green in the 19th century because it appeared green in both daylight and artificial light. It was used for dyeing silk and cotton. The color, however, was not lightfast and was superseded by aniline greens.
Synonyms and Related Terms
lo-kao; Chinese green; buckthorn bark; vert-venus; vert-azof; vert-lumiere; Rhamnus globosa; Rhamnus chlorophorus; Rhamnus utilis
Soluble in alkalis (turns violet) and acids. Slightly soluble in water. Insoluble in alcohol, ether, carbon disulfide.
Sources Checked for Data in Record
- Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
- Encyclopedia Britannica, http://www.britannica.com Comment: "Rhamnales" Encyclopædia Britannica [Accessed October 9, 2001]
- F. Crace-Calvert, Dyeing and Calico Printing, Palmer & Howe, London, 1876 Comment: p. 301
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 283
- Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000