Coal tar and other petrochemicals are used to make synthetic organic colors. Inorganic colors are created through very simple chemical processes (most notably oxidation) or are available naturally in the form of earth. White opaque pigments used to give opacity and lighten other colors are examples of inorganic pigments. Examples of modern organic pigments include Quinacridone, Phthalocyanine, and Cadmium Red.
Modern paint consists mainly of two components: a binder and a pigment. The binder controls such properties as brushability, flowability, and durability while the pigment provides color. There are two main types of binders used in paint: organic and inorganic.
Organic binders include oils and resins that can be derived from natural sources or manufactured products. They are biodegradable and don't contain any heavy metals, but they can emit toxic substances during the curing process. Organic binders are most commonly used for water-based paints because they will not dry out when exposed to air. Some examples of common organic binders include linseed oil, terpentine, rosin, and walnut shell powder.
Inorganic binders consist of minerals and rock powders that have been ground up small enough to be used as paint additives. They are non-biodegradable and usually do contain some type of metal (such as zinc or titanium).
Synthetic organic pigments are carbon-based molecules created by combining petroleum compounds, acids, and other chemicals under high heat or pressure. After 1860, the procedures for synthesizing these chemicals on an industrial scale were devised, ushering in the modern era of consumer color.
These colors are very stable to heat, light, and moisture and can be used with ease in any medium including watercolor, gouache, ink, paint, and more.
The process of making synthetic organic pigments involves taking a starting material, such as a dye or a pigment molecule, and using chemistry to add different groups to it. These added groups help determine the color that will be produced when the pigment is made into a powder form and heated in air. There are two main types of synthetic organic pigments: dyes and lakes. Lakes are a mixture of several different colors while drums are single tones with varying levels of darkness.
Drums for example, would be useful when trying to create the effect of snow on trees in winter scenes. They also make interesting background colors when used in combination with other pigments. The deeper the color, the stronger the hue will be. Drums are usually only available in limited quantities so they are expensive. There are also soft pastels which are similar to drums in that they are composed of colored waxes but they tend to be less durable than drums.
When compared to organic pigments, inorganic pigments can survive harsh weather conditions and high temperatures; hence, they are frequently employed in paints and coatings, plastics, building materials, printing ink, and other applications. In addition, they are useful for creating unique colors that cannot be achieved with dyes.
Inorganic pigments are commonly derived from minerals or glass. They come in an almost limitless variety of colors and shapes. The most common examples include black, white, red, yellow, blue, green, and violet.
Paints containing large amounts of pigment produce a much darker color than one might expect based on the amount of binder present. This is because large quantities of pigment reduce the lightness of the paint dramatically. As a result, artists often have to add some lighter colored paint to their works to make them appear natural. Paints that contain small amounts of pigment by volume, such as those used for fine art, require less additive to achieve the same effect.
Inorganic pigments were originally only available in limited colors, but modern technology has enabled manufacturers to create virtually any color you can think of. Some popular synthetic colors include phthalo blue, phthalo green, and prussian blue.
Since early people began painting on cave walls, iron oxide pigments, whether natural or manufactured, have been utilized as colorants. Several iron oxide minerals are used to make natural pigments: Hematite is the source of red pigments. Limonite is the source of yellow and brown colors such as ochres, sierras, and umbers. Goethite is the source of blue-black pigment called "ultramarine".
In addition to these natural pigments, man has created many other types of colors with metal oxides. These include violet, purple, and pink tuffs, and orange, red, and yellow sandstones.
Hematite is also used as a white pigment in paints because it does not yellow over time like other common white pigments such as talc or calcium carbonate.
Metal oxides are insoluble particles that remain in the paint film and act as light filters. They allow certain wavelengths of light to pass through while blocking others. This helps create different colors when light hits the surface of the painted object. For example, sunlight passing through a red paint film will cause it to look cooler than if it was only painted white. The same thing happens with colored glass; it just uses several different colors instead of one main color.
The type of metal oxide used as a pigment affects the color range that can be achieved by a paint job.