Difference between revisions of "Verditer"
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== Description == | == Description == | ||
| − | Synthetically prepared green or blue [[basic%20copper%20carbonate|basic copper carbonate]]. Verditer was an inexpensive pigment that was manufactured in the 16th century by pouring copper nitrate on calcium carbonate (whiting), followed by washing and drying. | + | Synthetically prepared copper-based green or blue [[basic%20copper%20carbonate|basic copper carbonate]]. Verditer was an inexpensive pigment that was manufactured in the 16th century as a replacement for the more expensive azurite and malachite pigments. Chemically, blue verditer is the same as azurite, while green verditer is chemically the same as malachite. It was made by pouring copper nitrate on calcium carbonate (whiting), followed by washing and drying. At one time, blue verditer was manufactured on a large scale in England, and there are reports that 'the artificial blues from copper are probably more significant in medieval painting than all the rest (of the blue pigments) put together' (Thompson in Gettens and Stout: 98). Green verditer is mentioned in 17th c literature but it does not seem to have been as common as blue verditer, having a very pale color. Verditer was used for both distemper and oil based interior house paints, and has seen widespread use in wallpapers. See [[malachite|malachite]], and [[azurite|azurite]]. |
== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
| − | basic copper carbonate | + | basic copper carbonate, blue bice, green bice, Bremen blue, cendres blue, ashes blue |
| + | |||
| + | ==Properties of Blue Verditer== | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! scope="row"| Composition | ||
| + | | Cu3[OHCO3]2 | ||
| + | |- | ||
| + | ! scope="row"| Refractive Index | ||
| + | | 1.730, 1.758, 1.838 | ||
| + | |} | ||
| + | |||
| + | ==Properties of Green Verditer== | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! scope="row"| Composition | ||
| + | | Cu2[(OH)2CO3] | ||
| + | |- | ||
| + | ! scope="row"| Refractive Index | ||
| + | | 1.655, 1.18.75, 1.909 | ||
| + | |} | ||
| + | |||
| + | ==Microscopic Properties== | ||
| + | |||
| + | Blue verditer (synthetic azurite): In plane polarized light, a pale blue to blue-green color with spherulitic particles reported as approx. 5-10um in diameter. Broken spherules and fibers will also be present. In intact spherules, a dark central spot may be observed. Relief is moderate with RI>1.662. Under crossed polars, birefringence is strong with second-order interference colors masked by the (blue) body color. Extinction is incomplete, but an extinction cross may be visible in intact spherules. | ||
| + | |||
| + | Green verditer (synthetic malachite): In plane polarized light, similar to blue verditer but displaying a paler, greenish color. Spherules reported as approx. 2-10um in diameter. Broken spherules will also be present. In intact spherules, a dark central spot may be observed. Relief is moderate to low with RI>1.662. Under crossed polars, birefringence is strong with second to third-order interference colors masked by the (greenish) body color. An extinction cross may be visible in intact spherules. | ||
| + | |||
| + | |||
| + | ==Additional Images== | ||
| + | |||
| + | <gallery> | ||
| + | |||
| + | File:Blue verditer PPL 400x.jpg|Blue verditer, PPL, 400x | ||
| + | File:Blue verditer XPL 400x.jpg|Blue verditer, XPL, 400x | ||
| + | File:Blue bice_verditer PPL 1000x.jpg|Blue verditer, PPL, 100x | ||
| + | File:Blue bice_verditer XPL 1000x.jpg|Blue verditer, XPL, 1000x | ||
| + | File:Green verditer_Synthesized malachite PPL 400x.jpg|Green verditer (Kremer), PPL, 400x | ||
| + | File:Green verditer_Synthesized malachite XPL 400x.jpg|Green verditer (Kremer), XPL, 400x | ||
| + | |||
| + | </gallery> | ||
== Comparisons == | == Comparisons == | ||
[[media:download_file_493.pdf|Characteristics of Common Blue Pigments]] | [[media:download_file_493.pdf|Characteristics of Common Blue Pigments]] | ||
| + | |||
| + | ==Sources== | ||
| + | |||
| + | ''Artists' Pigments: A Handbook of their History and Characteristics'', Ashok Roy (ed.), National Gallery of Art, Washington DC, Vol. 2, 1993 | ||
| + | |||
| + | Eastaugh, N., et. al. ''The Pigment Compendium: a Dictionary and Optical Microscopy of Historical Pigments'', Butterworth-Heinemann, London, 2008 | ||
| + | |||
| + | R. J. Gettens, G.L. Stout, ''Painting Materials, A Short Encyclopaedia'', Dover Publications, New York, 1966 | ||
| + | |||
| + | R.D. Harley, ''Artists' Pigments c. 1600-1835'', Butterworth Scientific, London, 1982 | ||
| + | |||
[[Category:Materials database]] | [[Category:Materials database]] | ||
Revision as of 15:55, 27 September 2017
Description
Synthetically prepared copper-based green or blue Basic copper carbonate. Verditer was an inexpensive pigment that was manufactured in the 16th century as a replacement for the more expensive azurite and malachite pigments. Chemically, blue verditer is the same as azurite, while green verditer is chemically the same as malachite. It was made by pouring copper nitrate on calcium carbonate (whiting), followed by washing and drying. At one time, blue verditer was manufactured on a large scale in England, and there are reports that 'the artificial blues from copper are probably more significant in medieval painting than all the rest (of the blue pigments) put together' (Thompson in Gettens and Stout: 98). Green verditer is mentioned in 17th c literature but it does not seem to have been as common as blue verditer, having a very pale color. Verditer was used for both distemper and oil based interior house paints, and has seen widespread use in wallpapers. See Malachite, and Azurite.
Synonyms and Related Terms
basic copper carbonate, blue bice, green bice, Bremen blue, cendres blue, ashes blue
Properties of Blue Verditer
| Composition | Cu3[OHCO3]2 |
|---|---|
| Refractive Index | 1.730, 1.758, 1.838 |
Properties of Green Verditer
| Composition | Cu2[(OH)2CO3] |
|---|---|
| Refractive Index | 1.655, 1.18.75, 1.909 |
Microscopic Properties
Blue verditer (synthetic azurite): In plane polarized light, a pale blue to blue-green color with spherulitic particles reported as approx. 5-10um in diameter. Broken spherules and fibers will also be present. In intact spherules, a dark central spot may be observed. Relief is moderate with RI>1.662. Under crossed polars, birefringence is strong with second-order interference colors masked by the (blue) body color. Extinction is incomplete, but an extinction cross may be visible in intact spherules.
Green verditer (synthetic malachite): In plane polarized light, similar to blue verditer but displaying a paler, greenish color. Spherules reported as approx. 2-10um in diameter. Broken spherules will also be present. In intact spherules, a dark central spot may be observed. Relief is moderate to low with RI>1.662. Under crossed polars, birefringence is strong with second to third-order interference colors masked by the (greenish) body color. An extinction cross may be visible in intact spherules.
Additional Images
Blue verditer, PPL, 400x
Blue verditer, XPL, 400x
Blue verditer, PPL, 100x
Blue verditer, XPL, 1000x
Green verditer (Kremer), PPL, 400x
Green verditer (Kremer), XPL, 400x
Comparisons
Characteristics of Common Blue Pigments
Sources
Artists' Pigments: A Handbook of their History and Characteristics, Ashok Roy (ed.), National Gallery of Art, Washington DC, Vol. 2, 1993
Eastaugh, N., et. al. The Pigment Compendium: a Dictionary and Optical Microscopy of Historical Pigments, Butterworth-Heinemann, London, 2008
R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982