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[5]: 132 Once used as a medicine [6] [7] and pharmaceutical preparation, [8]: 176 [9] verdigris occurs naturally, creating a patina on copper, bronze, and brass, and is the main component of a historic green pigment used for artistic purposes from antiquity until the late 20th century, including in easel painting, polychromatic sculptures, and ...
Kuro is black in Japanese and kuro-shibuichi is different from other variants in the table, being a mixture of shibuichi (~40%) and shakudō (~60%) with around 1% of gold (proportions could be, for example, 9.9% silver, 87.3% copper, and 2.8% gold). Kuro-shibuichi will develop a black patina which is different from the black patina of shakudo.
One example of a traditional Japanese patination for mokume-gane is the use of the niiro process, usually involving rokushō, a complex copper verdigris compound produced specifically for use as a patina. The piece to be patinated is prepared, then immersed in a boiling solution until it reaches the desired color, and each element of a compound ...
Brown or black can be used as a base color for copper patina. If the amount of chlorides decreases the color will be more bluish-green, if carbonate decreases, more yellow-green. [27] Black for copper. Solution of sodium polysulfide 2.5%, items must be submerged in the solution after color developing, wash, dry and wax or varnish colored object ...
Patina is also found on slip rings and commutators. This type of patina is formed by corrosion, what elements the air might hold, residue from the wear of the carbon brush, and moisture; thus, the patina needs special conditions to work as intended. Patinas can also be found in woks or other metal baking dishes.
In North America, copper mining began with marginal workings by Native Americans. Native copper is known to have been extracted from sites on Isle Royale with primitive stone tools between 800 and 1600. [12] Copper metallurgy was flourishing in South America, particularly in Peru around 1000 AD; it proceeded at a much slower rate on other ...
Interior of the Nott Memorial, with the Mandeville Gallery on the second floor. The Mandeville Gallery is an art gallery, located on the second floor of the Nott Memorial at Union College, Schenectady, New York, United States. The gallery opened in 1995 and is dedicated to exhibiting work by nationally recognized, contemporary artists exploring ...
The Pahaquarry Copper Mine is an abandoned copper mine located on the west side of Kittatinny Mountain presently in Hardwick Township [2] in Warren County, New Jersey in the United States. Active mining was attempted for brief periods during the mid-eighteenth, mid-nineteenth, and early twentieth centuries but was never successful despite ...