Paint

Dried green paint

Paint is the general term for a family of products used to protect and add color to an object or surface by covering it with a pigmented coating. Paint can be applied to almost any kind of object. It is used for aesthetic purposes, such as in producing works of art, and for practical purposes, such as in coating and protecting buildings, vehicles, and industrial machinery. Paint is also used to make signs for advertising and directing traffic.

Components

Both professional and amateur artists can take advantage of the wide variety of artists' paints available.

A paint generally has three types of components: a binder, a diluent, and additives. Of these, only the binder is absolutely required. It is the part that eventually solidifies to form the dried paint film. Typical binders include synthetic or natural resins, such as acrylics, polyurethanes, polyesters, melamines, oils, and latex.

The diluent serves to adjust the viscosity of the paint. It is volatile and does not become part of the paint film. Typical diluents include organic solvents such as alcohols, ketones, and esters. Water is also a common diluent. Sometimes volatile synthetic resins also serve as diluents.

Components other than the binder and diluent are called additives. Typical additives include pigments, dyes, catalysts, thickeners, stabilizers, emulsifiers, texturizers, adhesion promoters, and flatteners (de-glossing agents).

After application, the paint solidifies and becomes tack-free. Depending on the type of binder, this hardening may be a result of curing (polymer formation), evaporation, or cooling. The curing process usually involves cross-linking of the molecules of the binder, usually in the presence of a catalyst. Cured-film paints can be either solvent-borne or waterborne.

Some waterborne paints are emulsions of solid binders in water, and they are often referred to simply as "emulsions". When the diluent evaporates, the molecules of the binder coalesce and form polymers, leaving a solid film. Such emulsion paints are also known as latex paints. The polymer itself is not soluble in water, and as a result the paint is water resistant after it has dried.

Some paint films are formed by cooling of the binder. For example, wax paints are liquid when warm and harden upon cooling.

Art

Main article: Painting

The Mona Lisa is the most recognizable artistic painting in the Western world.

Since the time of the Renaissance, siccative (drying) oil paints (containing primarily linseed oil) have been the most commonly used type of paints in the fine arts. In the twentieth century, however, water-based paints—including watercolors and acrylic paints—became very popular, based on the development of latex and acrylic pigment suspensions. Milk paints (also called casein), in which the medium is derived from milk, were popular in the nineteenth century and are still available today. Egg tempera, in which the medium is an emulsion of egg yolk mixed in oil, is still in use as well, as are wax-based paints. Gouache is a form of watercolor paint that was also used in the Middle Ages and Renaissance for manuscript illumination. The pigment was often made from ground semiprecious stones, such as lapis lazuli, and the binder was made from either gum arabic or egg white. Gouache is commercially available today. Poster paint is usually used for artwork by children.

Pigment

Pigments, usually insoluble powders, are used both to provide color, and to make paint opaque, thus protecting the substrate from the harmful effects of ultraviolet light while also increasing a paint's hiding power.

Some pigments are toxic, such as those used in lead paint. Paint manufacturers replaced lead white with a less toxic substitute, which can even be used to color food titanium white (Titanium Dioxide) which was first used in paints in the 19th century. The titanium white used in most paints today is often coated with silicon or aluminum oxides for better durability.

Some newer paints - called prism paint - can produce effects where the color changes depending on the angle (orientation) at which it is viewed. Modern U.S. and Canadian banknotes, specifically the newer higher denomination notes, have this effect on them. This effect is produced by having pigment molecules that are long and thin and are meant to dry in a specific orientation, with different ends of the molecule being different colors.

ADDN777777777 In biology, pigment is any material resulting in color in plant or animal cells which is the result of selective absorption. Some biological material has so-called structural colour, which is the result of selective reflection or iridescence, usually done with multilayer structures. Unlike structural colour, pigment color is the same for all viewing angles. Many biological structures, such as skin, eyes, fur and hair contain pigments (such as melanin) in specialised cells called chromatophores. Butterfly wings typically contain structural colour, although many of them contain pigment as well. Creatures that have deficient pigmentation are called albinos.

In the coloring of paint, ink, plastic, fabric and other material, a pigment is a dry colorant, usually an insoluble powder. There are both natural and synthetic pigments, both organic and inorganic ones. Pigments work by selectively absorbing some parts of the visible spectrum (see light) whilst reflecting others.

A distinction is usually made between a pigment, which is insoluble, and a dye, which is either a liquid, or is soluble. There is a well-defined dividing line between pigments and dyes: a pigment is not soluble in the vehicle (or matrix) while a dye is. From this follows that a certain colourant can be both a pigment and a dye depending on in which vehicle it is used. In some cases, a pigment will be made by precipitating a soluble dye with a metallic salt. The resulting pigment is called a "lake". Fugitive pigments are non-permanent pigments. 777777777

Application

Paint can be applied as a solid, a gaseous suspension or a liquid. Techniques vary depending on the practical or artistic results desired.

As a solid (usually in industrial and automotive applications), the paint is applied as a very fine powder, then baked at high temperature. This melts the powder and causes it to adhere (stick) to the surface. The reasons for doing this involve the chemistries of the paint, the surface itself, and perhaps even the chemistry of the substrate (the overall object being painted).

As a gas or as a gaseous suspension, the paint is suspended in solid or liquid form in a gas that is sprayed on an object. The paint sticks to the object. The reasons for doing this include:

• the application mechanism is air and thus no solid object ever touches the object being painted;
• the distribution of the paint is very uniform so there are no sharp lines
• it is possible to deliver very small amounts of paint or to paint very slowly;
• a chemical (typically a solvent) can sprayed along with the paint to dissolve together both the delivered paint and the chemicals on the surface of the object being painted;
• some chemical reactions in paint involve the orientation of the paint molecules.

In the liquid application, paint can be applied by direct application using brushes, paint rollers, blades, other instruments, or body parts. Examples of body parts include fingerpainting, where the paint is applied by hand, whole-body painting (popular in the 1960s avant-garde movement), and cave painting, in which a pigment (usually finely-ground charcoal) is held in the mouth and spat at a wall (Note: some paints are toxic and might cause death or permanent injury).

Rollers generally have a handle that allows for different lengths of poles which can be attached to allow for painting at different heights. Generally, roller application takes two coats for even color. A roller with a thicker nap is used to apply paint on uneven surfaces. Edges are often finished with an angled brush.

After liquid paint is applied, there is an interval during which it can be blended with additional painted regions (at the "wet edge") called "open time." The open time of an emulsion paint can be extended by adding white spirit, similar glycols such as Dowanol™ (propylene glycol ether) or commercial open time prolongers. This can also facilitate the mixing of different wet paint layers for aesthetic effect.

Paint may also be applied by flipping or spraying the paint, dripping, or by dipping an object in paint.

Product Variants

• Wood stain is a type of paint that is very "thin," that is, low in viscosity, and formulated so that the pigment penetrates the surface rather than remaining in a film on top of the surface. Stain is predominantly pigment or dye and solvent with little binder, designed primarily to add color without providing a surface coating.
• Varnish and shellac provide a protective coating without changing the color. They are paints without pigment.
• Lacquer is usually a fast-drying solvent-based paint or varnish that produces an especially hard, durable finish.
• An enamel paint is a paint that dries to an especially hard, usually glossy, finish. Enamel can be made by adding varnish to oil-based paint.
• Fingerpaint
• Inks are similar to paints, except they are typically made using dyes exclusively (no pigments), and are designed so as not to leave a thick film of binder.
• Titanium dioxide is extensively used for both house paint and artist's paint, because it is permanent and has good covering power. Titanium oxide pigment accounts for the largest use of the element. Titanium paint is an excellent reflector of infrared, and is extensively used in solar observatories where heat causes poor seeing conditions.
• Anti-climb paint is a non-drying paint that appears normal whilst being extremely slippery. It is usually used on drainpipes and ledges to deter burglars and vandals from climbing them, and is found in many public places. When a person attempts to climb objects coated with the paint, it rubs off onto the climber, as well as making it hard for them to climb.

History

Ancient painted walls, to be seen at Dendera, Egypt, although exposed for many ages to the open air, still possess a perfect brilliancy of color, as vivid as when painted, perhaps 2000 years ago. The Egyptians mixed their colors with some gummy substance, and applied them detached from each other without any blending or mixture. They appeared to have used six colors: white, black, blue, red, yellow, and green. They first covered the field entirely with white, upon which they traced the design in black, leaving out the lights of the ground color. They used minium for red, and generally of a dark tinge.

Pliny mentions some painted ceilings in his day in the town of Ardea, which had been executed at a date prior to the foundation of Rome. He expresses great surprise and admiration at their freshness, after the lapse of so many centuries.

See also lacquer, varnish, fresco

Biological & organic pigments

• Heme/porphyrin-based: chlorophyll, bilirubin, hemocyanin, hemoglobin, myoglobin
• Light-emitting: luciferin
• Lipochromes:
  • Carotenoids: alpha and beta carotene, anthocyanin, lycopene, rhodopsin
  • Xanthophylls: canthaxanthin, zeaxanthin, lutein
• Photosynthetic: chlorophyll, phycobilin
• Organic: Pigment Red 170, phthalocyanine, Phthalo Green, Phthalo Blue,Alizarin, Alizarin Crimson, crimson, Indian Yellow, indigo, quinacridone, Quinacridone Magenta, woad.
• Resin: gamboge
• Polyene enolates: a class of red pigments unique to parrots

• Other: hematochrome, melanin, Phthalocyanine blue, urochrome, Van Dyke brown

Inorganic pigments

• Carbon pigments: bone black (also known as bone char), carbon black, ivory black, vine black, lampblack, Mars black
• Cadmium pigments: cadmium pigments, Cadmium Green, Cadmium Red, Cadmium Yellow, Cadmium Orange
• Iron pigments: Caput Mortuum, Prussian blue, oxide red, red ochre, Sanguine, Venetian red
• Chromium pigments: Chrome Green, chrome yellow
• Cobalt pigments cobalt blue, cerulean blue
• Lead pigments: lead white, Naples yellow, Cremnitz White, Foundation White, red lead
• Copper pigments: Paris Green, verdigris
• Titanium pigments: titanium dioxide, titanium white
• Sulfur pigments: ultramarine, Ultramarine Green Shade, French Ultramarine, vermilion
• Chrome pigments: viridian
• Zinc pigments: zinc white
• Clay earth pigments: sienna, raw sienna, burnt sienna, umber, raw umber, burnt umber, yellow ochre

External links

• History of Paint
• 20 recipes for homemade paint (text)
• Homemade Paint Recipes for Children
• The Quest of Purchasing Oil Paints
• Comparing Commercial Paints FAQ
• For a glossary of terms used in the paint industry go to Oil & Colour Chemists' Association and click on Paintopedia.
• Pigments through the ages
• Earliest evidence of art found

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

• Paint  ^history
• Pigment  ^history

The history of this article since it was imported to New World Encyclopedia:

• History of "Paint"

Note: Some restrictions may apply to use of individual images which are separately licensed.