Color Swatch created using heavy application/diluted application and was applied on cold press watercolor paper (150 lb) material.
This color contains the following pigments:
PB66—Indigo
Pigment Type
synthetic, organic
Chemical Name
2,2’-Bis(2,3-dihydro-3- oxoindolyliden)
Chemical Formula
C16H10N2O2
Properties
Indigo is a deep blue pigment, almost violet dye that can be laked as a pigment.
Permanence
Indigo is fugitive. Indigoid Blue is the famous blue dye used in many blue jeans and other denim products, famous for the way it fades! Although a few paint manufacturers offer a genuine indigo color based on PB66, it should be used only for applications that are not permanent, or where the color is required for historic reasons. Most paint manufacturers replicate this historic hue with other more permanent pigments.
Toxicity
Although natural indigo is known to be mildly toxic, its toxicity is believed to be the result of other natural alkoids found in plant sources, not of the indigo dye itself. The acute and chronic toxicity of synthetic indigo dyes has been studied and has been found to be very low. A form of indigo designated FD&C Blue No. 2 is used as a colorant in food and cosmetics.
History
Indigoid Blue is a synthetic version of Indigo, a famous dye and laked pigment that has been used since ancient times. The chemical compound that constitutes the indigo dye is called indigotin. More than 30 species of plants, found in many parts of the world, can be used to produce indigo dye. Indigo dye became the rage in Europe during the late Middle Ages. Although genuine indigo from plant sources is available, only the synthetic version is now used in commercial dye and pigment products. Genuine Indigo is designated NB1 (Natural Blue 1). The synthetic dye molecule was first synthesized by Bäyer in 1878, and it later became available as a commercial dye, quickly replacing natural sources.
Alternate Names
Indigoid Blue
PG7—Phthalo Green
Pigment Type
organic
Chemical Name
polychlorinated copper(II) phthalocyanine
Chemical Formula
C32H3Cl13CuN8 to C32HCl15CuN8 or C32H16CuN8Cl15 (PG7) or C32Br6Cl10CuN8 (PG36)
Properties
Phthalo Green is a transparent, cool, bright, high intensity color used in oil and acrylics. It comes from a Phthalocyanine Blue pigment where most of the hydrogen atoms have been replaced with chlorine, forming highly stable molecules. It has similar pigment properties and permanence to Phthalo Blue. It is slow drying and an excellent base color for mixing a range of bright greens. Phthalo Green is considered a very good alternative to Viridian because it is intense and mixes well and can be used to emphasize mineral colors in various tints. However, its tinting strength is very high, so it can overpower other colors. This pigment most closely resembles the discontinued and toxic Verdigris.
Permanence
Phthalo Greens are completely lightfast and resistant to alkali, acids, solvents, heat, and ultraviolet radiation. They are currently used in inks, coatings, and many plastics due to their stability and are considered a standard pigment in printing ink and the packaging industry.
Toxicity
Phthalo Green has no significant hazards, but it contained PCBs (polychlorinated biphenyls) until 1982.
History
This bright blue-green was developed in 1935 and has been in use since 1938.
Alternate Names
Bocour Green, Cyan Green, Intense Green, Monastral Green, Phthalocyanine Green, Rembrandt Green, Thalo Green, Winsor Green.
