CHAPTER 2: Pigments

Pigments are the particles that give art media their color. Made from ground minerals or manufactured compounds, pigments have been valued for their use in fine art and traded throughout history. In the last century, there has been considerable scientific progress in pigment manufacturing, giving artists a large and exciting collection to work with. Today, it’s important how various pigments behave and interact to gain insight into effective color use. This chapter covers the following:

• Pigment Properties

• A History of Paint

• Pigment Quality Chart

PIGMENT PROPERTIES

In various art media, pigment (in powdered form) is held together by a binder, such as oil, acrylic polymer, or gum arabic. The pigments are evenly distributed and suspended (not dissolved) in the binder. The binder, in tandem with other ingredients, determines the style and flow of the medium onto a drawing or painting surface. However, the pigment itself has specific qualities that allow for interesting variations—from a pigment’s opacity to its ability to stain and tint. Learn about the most important properties that distinguish pigments, and use the chart shown here as a consolidated reference.

PIGMENT BINDERS

MEDIUM/ART TOOL	BINDER
Watercolor paint	Gum arabic
Gouache paint	Gum arabic
Acrylic paint	Acrylic polymer dispersion
Oil paint	Oil (such as linseed)
Colored pencil	Wax or kaolin clay
Soft pastel	Methyl cellulose, gum arabic, or gum tragacanth
Oil pastel	Oil and wax

PAINT TOXICITY

Some paint colors contain toxic metals, so it’s important to handle them with care. Limit contact with your skin and eyes, and avoid inhaling or ingesting them. Below are a few paints with toxicity levels that call for consideration as you paint, with the offending ingredients in parentheses. Remember: If a paint name contains the word “hue,” it is most likely a nontoxic substitute for the original pigment.

• Cadmium red, yellow, and orange (cadmium)

• Cerulean blue (cobalt)

• Chrome green, yellow, and orange (chromates and/or lead)

• Cobalt blue, green, violet, or yellow (cobalt)

• Emerald or Paris green (copper acetoarsenite)

• Flake white (lead)

• Manganese blue and violet (manganese)

• Naples yellow (lead and antimony)

• Vermilion (mercury)

• Zinc sulfide white (zinc sulfide)

• Zinc yellow (chromate)

A HISTORY OF PAINT

The very first “paint” was made from charcoal or earth pigments such as limonite, hematite, red ochre, yellow ochre, umber, burnt bones, and white calcite, which was then ground up into a paste and mixed with binders of spit, blood, urine, vegetable juices, or animal fat. Humans applied this paint using twigs, feathers, or animal hair—often they even blew the paint through hollow bones to produce an “airbrush” effect.

The Greeks and Romans discovered the use of wax, resin, and eggs as a binding vehicle, while the Egyptians discovered and used earth pigments. The Middle Ages brought the discovery of ultramarine (blue), which was used extensively in representations of the Virgin Mary’s garments as a symbol of purity. By the 15th century, walnut and linseed oil began to replace egg as a binder, paving the way for a far more versatile medium: oil paint. This ushered in a new era of advancements in an artist’s ability to depict realism in perspective, picture-plane depth, luminosity, enhanced color, and more nuanced simulations of light and shadow.

The 19th century, which marked the beginning of the Modern Age, brought both the inventions of watercolor and the collapsible tin paint tube, revolutionizing the painting world and leading to a new era of color. No longer bound by grinding their own pigments, artists founded color-based movements such as Impressionism and Fauvism. Simultaneously, new and more vivid pigments burst onto the scene as a reaction to this new era of color liberation. The Contemporary Age, starting in 1900, brought artists the invention of both water-based paint (acrylics) and synthetic pigments, touted for their unparalleled brilliance of hue, lightfastness, and translucency.

Today artists have access to both tried-and-true mediums and new advancements in the art world. What a fabulous time to be an artist!

Ancient Paintings Cueva de los Manos in Patagonia, Argentina, features colorful and lively ancient cave paintings that date between 9,500 and 13,000 years old. Many of the hands are stenciled, suggesting the use of an airbrush technique.

INORGANIC VS. ORGANIC

There are two basic pigment types: inorganic and organic. Inorganic pigments come from the earth or are manufactured from non-carbon substances. These include earth pigments such as yellow ochre and burnt umber. Synthetic organic pigments are laboratory-created carbon compounds. Sometimes called “modern” pigments, they are often more intense than inorganic pigments. Many of them display beautiful transparency and promising lightfastness (resistance to fading) qualities.

Inorganic pigments:

• Alizarin crimson

• Burnt umber

• Prussian blue

• Raw umber

• Ultramarine blue

• Yellow ochre

Organic pigments:

• Azo yellow

• Hansa yellow

• Perylenes

• Phthalocyanines

• Pyrroles

• Quinacridones

PIGMENT OPACITY

Pigments are characterized as either transparent or semi-transparent, semi-opaque, or opaque. Opaque pigments more effectively block light from hitting the substrate or surface beneath, whereas transparent pigments allow light to pass through and reflect the substrate back to the viewer. Opaques provide more coverage and appear to advance toward the viewer, so they are better suited for foreground objects and highlights. Transparents create luminous and atmospheric effects in paintings and are great for suggesting depth in shadows. Transparents also make wonderful glazes.

Here you can view highly opaque pigments (top row) versus highly transparent pigments (bottom row). To know the qualities of the pigments in your own palette, it’s a good idea to create a chart like this with your paints. Simply paint a stroke over a black line (such as permanent marker) on your painting surface.

STAINING VS. NONSTAINING

Pigments are classified as staining or nonstaining. Staining pigments, such as alizarin crimson or the phthalocyanines, immediately absorb into the paper’s surface and are impossible to lift or dab away completely. Nonstaining pigments, such as burnt umber or the cadmiums, sit on the surface of the paper and lift away easily. This pigment quality is most relevant to watercolor, particularly when working with techniques that call for dabbing away the pigment. If you want to use staining colors but need the ability to lift them away, you can apply watercolor lifting preparation medium to your paper before applying paint, which makes lifting possible with any pigment.

To test the staining quality of a paint, apply a rich stroke of the color to paper and allow it to dry. Use a wet brush to loosen an area of pigment and dab with a paper towel. The more color that remains, the higher the staining quality. Above is a staining test performed with phthalo blue (staining) and burnt umber (nonstaining).

TINTING

When using pigments with a strong tinting quality, a little goes a long way. Knowing the tint strength is helpful when mixing colors; strong paints can overpower those with weak tinting strength, so you will have to adjust your mixes accordingly. Many highly tinting pigments are also highly staining.

In this example, see how a highly tinting pigment can overpower a pigment of lesser tinting strength. The top row shows lemon yellow mixed with cobalt blue in equal parts (both moderate in tinting strength), which yields a soft green. The bottom row shows lemon yellow mixed with phthalo blue in equal parts. Phthalo blue, a highly tinting pigment, clearly dominates the mix.

MASSTONE VS. UNDERTONE

When assessing a paint, artists often refer to its masstone and undertone. Masstone is the paint as it appears in a thick scoop from the tube, whereas undertone is the paint as it appears thinly over a white support. A pigment’s masstone and undertone can vary quite a bit in hue and value.

LIGHTFASTNESS

Lightfastness refers to the ability of pigment to resist fading over time, particularly when exposed to UV light. Lightfast pigments are not prone to fading and are considered to be more permanent than nonlightfast pigments. Nonlightfast—or fugitive—pigments lighten and lose their intensity quicker. The American Society for Testing and Materials (ASTM) has developed a rating system for lightfastness; a paint’s rating is visible on its tube. It is measured on a scale of I to V, with I and II being the only acceptable ratings for professional artists.

Permanent rose (acrylic)

Phthalo green (acrylic)

PAINT VARIATION

Manufacturers offer “hue” varieties of popular paint colors—especially in student-grade paint lines. A hue is not made purely of the pigment specified in the name; instead, it is a mixture of other pigments to match the hue of the original. Manufacturers often do this to reduce cost or toxicity. Paint names, formulations, and properties may also vary between manufacturers; for this reason, many artists are loyal to one brand of paints.

PIGMENT QUALITY CHART

REDS
Swatch
Paint/Pigment Name	Alizarin crimson
Color	blue-leaning red
Pigment Type	organic
Transparency	transparent
Staining Ability	high
Lightfastness (ASTM)	II or III
Swatch
Paint/Pigment Name	Cadmium red
Color	yellow-leaning red
Pigment Type	inorganic
Transparency	opaque
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Quinacridone red
Color	blue-leaning red
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Naphthol red
Color	yellow-leaning red
Pigment Type	synthetic organic
Transparency	semi-opaque
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Perylene red
Color	slightly blue-leaning red
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	medium
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Pyrrole red
Color	yellow-leaning red
Pigment Type	synthetic organic
Transparency	semi-opaque
Staining Ability	high
Lightfastness (ASTM)	I
PURPLES
Swatch
Paint/Pigment Name	Dioxazine purple
Color	blue-leaning violet
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Quinacridone violet / Quinacridone magenta
Color	red-leaning violet
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	medium
Lightfastness (ASTM)	I
BLUES
Swatch
Paint/Pigment Name	Ultramarine blue
Color	red-leaning blue
Pigment Type	inorganic
Transparency	semi-transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Phthalo blue
Color	yellow-leaning or red-leaning
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Manganese blue
Color	yellow-leaning blue
Pigment Type	inorganic
Transparency	transparent
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Cobalt blue
Color	slightly yellow-leaning blue
Pigment Type	inorganic
Transparency	semi-transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Cerulean blue
Color	yellow-leaning blue
Pigment Type	inorganic
Transparency	semi-transparent
Staining Ability	low
Lightfastness (ASTM)	I
GREENS
Swatch
Paint/Pigment Name	Phthalo green
Color	blue-leaning green
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Cobalt green
Color	yellow-leaning green
Pigment Type	inorganic
Transparency	semi-transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Terre verte
Color	olive green
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Viridian
Color	blue-leaning green
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	I
YELLOWS
Swatch
Paint/Pigment Name	Aureolin
Color	primary yellow
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	II
Swatch
Paint/Pigment Name	Hansa yellow / Lemon yellow
Color	bright blue-leaning yellow
Pigment Type	synthetic organic
Transparency	semi-transparent
Staining Ability	low to medium
Lightfastness (ASTM)	II
Swatch
Paint/Pigment Name	Nickel azo yellow
Color	brownish yellow
Pigment Type	synthetic organic
Transparency	transparent
Staining Ability	medium
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Cadmium yellow
Color	red-leaning yellow
Pigment Type	inorganic
Transparency	opaque
Staining Ability	low
Lightfastness (ASTM)	I
EARTH COLORS
Swatch
Paint/Pigment Name	Burnt sienna
Color	red-leaning brown
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Burnt umber
Color	red-leaning brown
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Raw sienna
Color	yellow-leaning brown
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Raw umber
Color	varied; often gray-or green-leaning brown
Pigment Type	inorganic
Transparency	transparent
Staining Ability	low
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Yellow ochre
Color	orange-leaning yellow
Pigment Type	inorganic
Transparency	opaque
Staining Ability	low
Lightfastness (ASTM)	I
BLACKS
Swatch
Paint/Pigment Name	Ivory or bone black
Color	warm black
Pigment Type	inorganic
Transparency	semi-transparent
Staining Ability	high
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Mars black
Color	cool black
Pigment Type	inorganic
Transparency	opaque
Staining Ability	high
Lightfastness (ASTM)	I
WHITES
Swatch
Paint/Pigment Name	Titanium white
Color	blue-leaning white
Pigment Type	inorganic
Transparency	opaque
Staining Ability	N/A
Lightfastness (ASTM)	I
Swatch
Paint/Pigment Name	Zinc white / Chinese white
Color	blue-leaning white
Pigment Type	inorganic
Transparency	semi-opaque
Staining Ability	N/A
Lightfastness (ASTM)	I
Note: The colored circles shown are for illustrative purposes only. Actual paint colors may not match exactly due to variations in printing ink.