Before we can begin discussing the various definitions of Pigments and their purpose within Art; it is important to clearly outline what color itself is.
Color and light are mutually inclusive properties of reality. Color exists due to the various wavelengths of light, reflecting, refracting and emanating off of particles. Our eyes perceive the light waves that bounce off these particles, coloring our world.
Pigments are finely ground colored material that make up the color of paints, colored leads and pastels. Pigment is the basis of all colored art materials. Further distinctions can be made, regarding the origins of various colors. As light reflects off of these finely ground substances, the light that is reflected and enters our eyes colors our world.
Organic Vs. Inorganic
The distinctions between organic and inorganic pigments are, at first glance, seemingly contrary to intuition. An understanding of both types of pigments is essential to an artists’ understanding of color theory.
Organic (aka modern – 20th century colors) pigments derive from synthetically produced colorants. These pigments involve complex carbon based chemistry, and include a variety of materials such as animal, vegetable and other synthetically derived materials (petroleum, coal tar and natural gases). Vibrant and Bright in color, Organic pigments have an incredible tinting/dyeing strength and tend to be transparent. Their Lightfast Quality (see definition below) ranges from fugitive to strong. On the whole, Organic pigments tend to be rather expensive.
Anthaquinone Blue, Diarylide Yellow, Dioxazine Purple, Hansa Yellows, Phthalocyanine Blues, Quinacridones.
Inorganic Pigments (mineral) are those produced from naturally mined minerals as well as synthetically manufactured pigments.
Lightfast/Lightfastness refers to a pigments or dyes tendency to discolor when exposed to light for prolonged periods of time. A Fugitive color is one that loses its pigmentation quickly. These pigments are impermanent and will shift in color (i.e. lighten, darken, or otherwise change in appearance when exposed to environmental factors).
The differences between Organic and Inorganic pigments
|Particulars||Inorganic Pigments||Organic Pigments|
|Source||Minerals||Chemically refined oil|
|Dyeing / Coloring Strength||Low||High|
|Light fastness||Very good||Vary from poor to good|
|Solubility||Insoluble in solvents||Have have little degree of solubility|
|Degree of safety||May be unsafe||Usually safe|
|Chemical Stability||Often sensitive||Usually good|
|Cost||Moderate||Mostly too expensive|
Artisans have employed some inorganic pigments for centuries and some for millennia. They are produced from either naturally mined pigments (sienna, umber, ochre) or synthetically manufactured pigments, (iron oxide, carbon black, etc). Inorganic pigments may also be produced using a combination of these two processes. Inorganic Pigments that are both mined and manufactured include the Cadmiums, Cobalts, and Titaniums.
The organic pigments are a group of colorants synthetically produced through complex carbon-containing chemistry involving various materials including petroleum, coal tar and natural gas. Many of these pigments have their roots in the chemistry of the 1800s, although widespread production didn’t really begin until the 1930s. Even though they have only been available for several decades, organic pigments have demonstrated remarkable abilities to withstand the impact of light and weather.
Obsolete Art Pigments – Part 1