Organic and Inorganic Pigment Characteristics

Paint, whether used to cover a house, an automobile or a canvas, derives its color from powdered pigments, each with its unique set of attributes. Over time, if you’re attentive to your colors’ behavior and do a bit of research, you’ll become familiar with the distinctive natures, strengths and weaknesses of your pigments and learn to use them to their best technical and aesthetic advantage.

But even without a lot of painting experience, you can pick up many hints about a pigment’s characteristics just by knowing whether it’s organic (mineral-based) or inorganic (carbon-based).

Inorganic pigments usually, but not always, have these characteristics:

  • heaviness in weight (because of the mineral content)
  • large particles
  • good wetting properties (because the particles don’t float)
  • leanness (which gives their colors a matte look)
  • low tinting strength
  • mass tones that gray down when mixed with white (creating more natural light effects)
  • light-to-dark shift within a family
  • high lightfast rating

Exceptions include Prussian blue and viridian—both are inorganic pigments that have high tinting strengths and small particle sizes.

Organic pigments tend to have the following characteristics:

  • lightness in weight (creating high volume)
  • small particle size
  • resistance to wetting (because the particles float and, therefore, need a dispersion agent)
  • fatness (giving them a natural gloss)
  • transparency or semitransparency
  • high tinting strength
  • mass tones that create intense tints when mixed with white (causing them to stay high key unless a complement is added, and creating less-natural light effects)
  • warm-to-cool shift within a family
  • good-to-excellent lightfast ratings

Exceptions are some of the historic organic pigments—such as rose madder and carmine—which have poor lightfast ratings and are prone to fading.

Koo Schadler, a board member of the Society of Tempera Painters, conducts workshops on egg tempera and old master painting. Author of the book Egg Tempera Painting, she’s a master painter of the Copley Society of Art in Boston. For more information about her book and her work, visit www.kooschadler.com

This article is an excerpt from the Brushing Up column “Know Your Pigments” in the May 2009 issue of The Artist’s Magazine,  available at www.northlightshop.com.

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