Blue verditer is the name given to artificial basic copper carbonate with approximately the same chemical composition as azurite. Refiner's dark blue verditer was used in watercolors and distemper during the 17th and 18th centuries. Our Refiner's dark blue verditer is made according to an English recipe of the 18th century.
|Pigment Names |
|Synonyms: ||English: bice; blue ashes, cendres blue, Sanders blue; mountain blue, copper blue, lime blue |
French: cendres bleu; bleu de montagne; bleu d'Allemagne
German: Verditer; Aschblau; Bergblau; Kalkblau
Italian: ceneri blu di pasta, azzurro della cenere; azzurro della magna
Portuguese: azul da cinza; azul da montanha
Spanish: azul de la ceniza; azul de la montaña
Latin: lapis armenius; azurium citramarinum
Origin and History
Blue verditer is the name given to artificial basic copper carbonate with approximately the same chemical composition as azurite. It is believed that blue verditer was a byproduct of silver refining. Numerous early recipes for its preparation are known; the best types appear to have been prepared at relatively low temperatures with a copper salt. "Refiner’s verditer" was considered the best type of copper carbonate and was widely used as house paint during the 17th and 18th centuries with continuing use up to the 19th century.
Our Refiner's dark blue verditer is made according to an English recipe of the 18th century that requires relatively low temperatures for its manufacture. This deep blue, slightly more greenish than natural azurite, lends itself well to consistent applications of color. Microscopically, blue verditer appears as tiny, rounded, fibrous aggregates, even in size and blue by transmitted light. It is similar in color to finely ground azurite.
Permanence and Compatibility
Blue verditer is stable in lime and is well suited for tempera and watercolor, but is liable to darken or become greenish in oil. However, it can be used with some success if it is mixed with lead white ground in oil. The white pigment lightens the blue and keeps it from appearing too dark. Painted swatches of our Refiner's dark blue verditer ground in oil show little change in color after five years.
Oil Absorption and Grinding
Verditer absorbs a medium amount of oil (23 g oil per 100 g of pigment).
Blue verditer contains copper, which can be toxic if inhaled or ingested. Care should be used in handling the dry powder pigment to avoid inhaling the dust. Pigment: Refiner's Dark Blue Verditer
|Pigment Information |
|Color: ||Blue |
|Colour Index: ||Pigment Blue 30 (77420) |
|Chemical Name: ||Basic Copper Carbonate |
|Chemical Formula: ||2CuCO3.Cu(OH)2 |
|ASTM Lightfastness Rating |
|Acrylic: ||Not Tested |
|Oil: ||Not Tested |
|Watercolor: ||Not Tested |
|Specific Gravity: ||3.70 |
|Hardness: ||3.5–4.0 |
|Refractive Index: ||α=1.73, β=1.758, γ=1.838 |
|Oil Absorption: ||23 g oil/100 g pigment |