Metallic pigment in acrylic medium and urine on canvas
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Andy Warhol (August 6, 1928 – February 22, 1987) was an American artist who was a leading figure in the visual art movement known as pop art.
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In the late 1970s and early 1980s, Andy Warhol focused for the first time on the exploration of abstraction. … … In December 1977 Warhol began the Oxidations, iridescent canvases made up of coppery yellows, oranges, and greens. Surprisingly, the only paint used by the artist in this very “painterly” work was the metallic copper background. Warhol invited friends and acquaintances to urinate onto a canvas covered in metallic paint in order to cause oxidation. The uric acid reacted with the copper in the paint removing components of the pure metal to form mineral salts. Some colours developed immediately while others like blue and green formed later on top of the red or brown copper oxides. Warhol and his collaborators experimented with both pattern and coloration by using a variety of metallic background paints and by varying the maker’s fluid and food intake.
More science behind the art:
Transition metals (such as copper) will form coloured compounds. The colour of the compound depends on the metal’s oxidation state and the type of accompanying ion present.
Substance
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Colour
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Substance
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Colour
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Copper(I) oxide
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Red
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Chromium (III) oxide
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Green
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Copper (II) oxide
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Black
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Potassium chromate (K2CrO4)
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Yellow
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Copper (II) sulfate
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Blue
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Potassium dichromate (K2Cr2O7)
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Orange
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Copper (II) carbonate
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Green
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| Andy Warhol, Oxidation Painting 1978 |
