In the seventeenth century, much like today, the terms "ivory black" and "bone black" were often used interchangeably. Both refer to a black pigment derived from the charring of animal bones, horns, and other organic materials. However, genuine ivory black, made specifically from charred ivory from elephant tusks, did exist. Due to the high cost of ivory, this form of the pigment was considered a luxury item and was likely reserved for special commissions or contexts where the expense could be justified, such as high-value artworks. In all likelihood, the "ivory black" used by Dutch seventeenth-century painters was often actually bone black, a more affordable alternative given the greater availability of its raw materials.
The differences between the two types of black pigment are subtle but noteworthy. True ivory black is generally more transparent and offers a richer, deeper black color that is slightly cooler or bluish in tone compared to bone black. On the other hand, bone black is less intense and has a slightly warmer, sometimes brownish undertone, making it ideal for underpainting. This made it particularly useful for areas requiring subtle warmth or depth, such as shadows in flesh tones or backgrounds with a more naturalistic appearance. Bone black was less intense than carbon black, providing artists with a versatile alternative for nuanced tonal work. Its opacity and texture also made it suitable for blending with whites or earth tones to create muted grays and browns.
Both pigments are produced by subjecting either fragments of ivory or animal bones to high temperatures in a controlled environment, typically in the absence of oxygen to prevent complete combustion. The specific temperatures and conditions can vary, which in turn affects the properties of the resulting pigment. Research indicates that these types of black pigments are among the most popular in European easel painting.
The brushing and drying characteristics of ivory black and bone black can vary depending on the specific formulation of the paint, including the type of binder used (e.g., oil, acrylic, watercolor), as well as any additives. However, some general observations can be made:
Ivory black generally has a smooth, buttery consistency that flows well off the brush, making it suitable for fine details as well as broader strokes. In oil form, ivory black can have a relatively slow drying time compared to other pigments. This allows for more extended blending and manipulation on the canvas.
Bone black can also offer a smooth brushing experience, but it may not flow as easily as ivory black. Its slightly grainier texture can provide a different tactile experience. Bone black tends to dry at a moderate rate in oil form, which is generally quicker than ivory black. This makes it less ideal for techniques that require a longer open time but better for layers that you want to dry more quickly.
Both pigments are versatile and can be used in various techniques, from glazing to impasto, depending on how they are formulated. They can also be mixed with other colors to achieve a range of tones and shades. However, artists may choose one over the other based on the specific requirements of a project, such as the need for a faster drying time or a particular tonal quality.
Beyond their use in paint, both ivory and bone black are also employed in printmaking, calligraphy, drawing inks, and other artistic applications due to their deep color and excellent tinting strength. While ivory black was traditionally made by grinding charred ivory in oil, it is now largely synonymous with bone black, which is made from various animal bones. The use of actual ivory has declined due to both its expense and ethical concerns related to the endangerment of species that are natural sources of ivory.
Bone Black in Vermeer's Painting
The presence of bone black has been detected only once in the black marble tiles of The Music Lesson(fig. 1). It was also added to natural ultramarine to tone down the white tiles in the same painting.
