Acrylic painting is a pictorial technique born in relatively recent times. The paints are produced with colored powders (pigments) mixed with an acrylic resin (almost exclusively of ketonic origin) of variable drying, usually fast, depending on the resins, pigments and the manufacturing factory.
Acrylic painting techniques are different styles of manipulating and working with polymer-based acrylic paints. Acrylics differ from oil paints in that they have shorter drying times (as little as 10 minutes) and are soluble in water. These types of paint eliminate the need for turpentine and gesso, and can be applied directly onto canvas. Aside from painting with concentrated color paints, acrylics can also be watered down to a consistency that can be poured or used for glazes.
A fundamental characteristic of acrylic colors, which differentiates them from traditional tempers, is their indissolubility once they are dry. It is therefore necessary a thorough cleaning of the brushes after the work; it is to be avoided that the color dries on the brushes, which must be rinsed in water and dried. If the color has dried on the brush you can dissolve it with alcohol or nitro thinner.
In relation to oil paints, acrylic paints give slightly less freedom in giving textures to paintings, however, similarly easy with them you can get all other effects from the impression of penetrating colors to spatial effects.
The supports can be the most disparate, from drawing sheets (like Bristol), to cardboard, to canvas, to canvas board, to wooden supports (even plywood). They are used, as well as for the execution of paintings, for wall decoration and that of the most disparate objects, their good strength combined with the relative cost-effectiveness and quick drying make it a widely used product. You can slow down the drying with a moderate addition of glycerine.
Characteristics of acrylic paint is the very quick drying, easy application and the translucency when dry. The acrylic defect is not to allow the shading technique, as it is done in oil painting. In fact, the shading with acrylics takes place at times, with steps allowing the passage from one tone to another, or with successive veils of diluted color that are laid on a dry color. The acrylic colors can be easily mixed together and as a diluent simple water is preferable, which can also be used to remove parts of color before drying.
Some types of acrylic colors are sensitive to light that makes them lighten, such as red-violet and blue-violet colors, because created with pigments derived from photosensitive organic chemicals, this phenomenon is obvious with an acrylic resin lacquer with UV filter that protects these colors.
For the other colors there is no need for fixative, as the acrylic resin that makes them makes them resist to light and atmospheric agents, including smog.
Painting with acrylics
Before the 19th century, artists mixed their own paints, which allowed them to achieve the desired color and thickness, and to control the use of fillers, if any. While suitable media and raw pigments are available for the individual production of acrylic paint, hand mixing may not be practical because of the fast drying time and other technical issues.
Acrylic painters can modify the appearance, hardness, flexibility, texture, and other characteristics of the paint surface by using acrylic media or simply by adding water. Watercolor and oil painters also use various media, but the range of acrylic media is much greater. Acrylics have the ability to bond to many different surfaces, and media can be used to modify their binding characteristics. Acrylics can be used on paper, canvas and a range of other materials, however their use on engineered woods such as medium-density fiberboard can be problematic because of the porous nature of those surfaces. In these cases it is recommended that the surface first be sealed with an appropriate sealer. Acrylics can be applied in thin layers or washes to create effects that resemble watercolors and other water-based media. They can also be used to build thick layers of paint—gel and molding paste media are sometimes used to create paintings with relief features. Acrylic paints are also used in hobbies such as train, car, house, and human models. People who make such models use acrylic paint to build facial features on dolls, or raised details on other types of models. Wet acrylic paint is easily removed from paint brushes and skin with water, whereas oil paints require the use of a hydrocarbon.
Acrylic paints are the most common paints used in grattage, a surrealist technique that became popular with the advent of acrylic paint. Acrylics are used for this purpose because they easily scrape or peel from a surface.
Acrylic artists’ paints may be thinned with water and used as washes in the manner of watercolor paints, but unlike watercolor the washes are not rehydratable once dry. For this reason, acrylics do not lend themselves to the color lifting techniques of gum arabic-based watercolor paints.
Acrylic paints with gloss or matte finishes are common, although a satin (semi-matte) sheen is most common. Some brands exhibit a range of finishes (e.g. heavy-body paints from Golden, Liquitex, Winsor & Newton and Daler-Rowney); Politec acrylics are fully matte. As with oils, pigment amounts and particle size or shape can affect the paint sheen. Matting agents can also be added during manufacture to dull the finish. If desired, the artist can mix different media with their paints and use topcoats or varnishes to alter or unify sheen.
When dry, acrylic paint is generally non-removable from a solid surface if it adheres to the surface. Water or mild solvents do not re-solubilize it, although isopropyl alcohol can lift some fresh paint films off. Toluene and acetone can remove paint films, but they do not lift paint stains very well and are not selective. The use of a solvent to remove paint may result in removal of all of the paint layers (acrylic gesso, et cetera). Oils and warm, soapy water can remove acrylic paint from skin.
An acrylic sizing should be used to prime canvas in preparation for painting with acrylic paints, to prevent Support Induced Discoloration (SID). Acrylic paint contains surfactants that can pull up discoloration from a raw canvas, especially in transparent glazed or translucent gelled areas. Gesso alone will not stop SID; a sizing must be applied before using a gesso.
The viscosity of acrylic can be successfully reduced by using suitable extenders that maintain the integrity of the paint film. There are retarders to slow drying and extend workability time, and flow releases to increase color-blending ability.
Preventing paint from drying out
Acrylics are often preferred because they dry faster on canvas than oil paints due to their polymer base. However, in some circumstances, the artist may want the paint to stay moist longer. A trick to keep paints from drying out is to spray a light mist of water over them occasionally. Moisture-retaining palettes also increase acrylic paint drying time, and can be substituted with a shallow container, a sheet of grease proof paper, or piece of wet watercolor paper.
Creating fluid paints
Fluid paints can be used like watercolors, or for glazing and washes. To create a more fluid texture, water is added to the paint. The ratio of paint to water depends on how thick the glaze is expected to be. An opaque glaze or paint consists of more paint than water, and will give a more solid color. A translucent glaze or paint will be the opposite, consisting of slightly more water than the opaque version, and will have a smoother texture. Translucent glazes show more of the colors underneath the paint compared to opaque glazes. Artist Keri Ippolito advises that the paint should be watered no more than 50 percent or the paint will not stick to the canvas. After mixing the paints, allow time for the air bubbles to rise to the surface. This will be crucial in many techniques, especially in pouring paints.
Acrylic paint glazes are often used to create more depth in an image. When glaze medium is applied to acrylic paint, the paint becomes more transparent and will reveal the layer of paint used beneath it, which modifies the color. This technique is commonly used to create more realistic images. Light colored glazes also have softening effects when painted over dark or bright images. Artists can mix glazes themselves, or can buy pre-mixed acrylic glazes.
It is best to wait for each layer to dry thoroughly before applying another coat. This will prevent the paint from smearing or leaving unwanted smudge marks. After the application of several layers, rubbing alcohol can be brushed or sprayed on to reveal colors from earlier layers.
Pour painting is an innovative way to use acrylic paints to create an art piece. Instead of using tools like brushes or knives to create a piece of art, fluid paints can be poured directly onto the surface and the canvas tilted to move the paint around. Pouring paints allows for the colors to blend naturally as they come in contact with each other. This technique can be done either one color at a time, or with multiple paints to maximize color blending. Pour painting can also be done with oil paints, but because those paints take a longer time to dry, the piece would have to be done over an extended period of time, or with wet paints. However, it should be noted that the subtle effects of the interaction of different liquid colors on drying can be partially lost during the drying process.