Acrylic paint is fast drying
paint containing pigment suspension in acrylic polymer emulsion. Acrylic paints
can be diluted with water, but become water-resistant when dry. Depending on
how much the paint is diluted (with water) or modified with acrylic gels,
media, or pastes, the finished acrylic painting can resemble a watercolor or an
oil painting, or have its own unique characteristics not attainable with other
media.
History
As early as 1934 the first usable
acrylic resin dispersion was developed by German chemical company BASF, which
was patented by Rohm and Haas. Between 1946 and 1949, Leonard Bocour and Sam
Golden invented a solution acrylic paint under the brand Magna paint. These
were mineral spirit-based paints. Acrylics were made commercially available in
the 1950s. A waterborne acrylic paint called "Aquatec" would soon
follow. Otto Rohm invented acrylic resin, which quickly transformed into
acrylic paint. In 1953, the year that Rohm and Haas developed the first acrylic
emulsions, Jose L. Gutierrez produced Politec Acrylic Artists' Colors in
Mexico, and Permanent Pigments Co. of Cincinnati, Ohio, produced Liquitex
colors. These two product lines were the very first acrylic emulsion artists'
paints. Water-based acrylic paints were subsequently sold as latex house
paints, as latex is the technical term for a suspension of polymer
microparticles in water. Interior latex house paints tend to be a combination
of binder (sometimes acrylic, vinyl, pva, and others), filler, pigment, and
water. Exterior latex house paints may also be a co-polymer blend, but the best
exterior water-based paints are 100% acrylic, due to elasticity and other
factors, but vinyl costs half of what 100 percent acrylic resins cost, and PVA
(polyvinyl acetate) is even cheaper, so paint companies make many combinations
of them to match the market.
Soon after the water-based
acrylic binders were introduced as house paints, artists and companies alike
began to explore the potential of the new binders. Water-soluble artists'
acrylic paints became commercially available in the 1950s, offered by Liquitex,
with high-viscosity paints similar to those made today becoming available in
the early 1960s. In 1963, Rowney (now part of Daler-Rowney since 1983) was the
first manufacturer to introduce an artist’s acrylic color in Europe, under the
brand name Cryla.
Techniques
Acrylic artist paints may be
thinned with water and used as washes in the manner of watercolor paints, but
the washes are not re-hydratable once dry. For this reason, acrylics do not
lend themselves to color lifting techniques as do gum arabic based watercolor
paints. Fluorescent acrylic paints lit by UV light. Paintings by Beo Beyond
Acrylic paints with gloss or
matte finishes are common, although a satin (semi-matte) sheen is most common;
some brands exhibit a range of finish (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 naturally
affect the paint sheen. Matting agents can also be added during manufacture to
dull the finish. The artist can mix media with their paints and use topcoats or
varnishes to alter or unify sheen if desired.
When dry, acrylic paint is
generally non-removable from a solid 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, etc. Oils can
remove acrylic paint from skin.
Only a proper, artist-grade
acrylic gesso should be used to prime canvas in preparation for painting with
acrylic (however, acrylic paint can be applied to raw canvas if so desired
without any negative effect or chemical reaction as would be the case with
oils). It is important to avoid adding non-stable or non-archival elements to
the gesso upon application. However, the viscosity of acrylic can successfully
be 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.
Painters and acrylic
Prior to 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 due to 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 adjust 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
that are literally sculptural. 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. Acrylic paint is easily removed from paint brushes and skin with water,
unlike oil paints that require the use of a hydrocarbon.
Acrylic paints are the most
common paints used in grattage. Grattage is a surrealist technique that became
popular with the release of acrylic paint. Acrylics are used for this purpose
because they easily scrape or peel from a surface.
Grades
Commercial Acrylic paints come in
three grades: "Artist" (or "Professional"),
"Student" (or "studio"), and "Scholastic".
• Artist Acrylics are designed
with the professional artist in mind. Highly pigmented with a focus on single
pigment colors for the cleanest mixing results, they tend to have viscosity
similar to oil paints and can thus hold a brush stroke for impasto
applications. Acrylics can be applied to canvas, boards, paper, panels, wood,
and a number of other prepared surfaces.
• Student Acrylics have working
characteristics similar to professional artist acrylics, but with lower pigment
concentrations, less expensive formulas, and a smaller range of colors. More
expensive pigments are generally replicated by hues. Colors are designed to be
mixed, although color strength is lower. Hues may not have the exact mixing
characteristics of full-strength colors.
• Scholastic Acrylics use less
expensive pigments as well as dyes in formulations that are safe for younger
artists, and economical for classroom use. The color range is limited to common
primary and secondary colors, and the actual pigments are unspecified. Because
scholastic acrylics use dyes as well as pigments, lightfastness may be poor.
Varieties
• Craft acrylics can be
used on surfaces besides canvas, such as wood, metal, fabrics, and ceramics.
They are used in decorative painting techniques and faux finishes, often to
decorate objects of ordinary life. Although colors can be mixed, pigments are
often not specified. Each color line is formulated instead to achieve a wide
range of pre-mixed colors.
• Heavy body acrylics are
typically found in the Artist and Student Grade paints, they are the best
choice for impasto or heavier paint applications. Heavy Body refers to the
viscosity or thickness of the paint. They will hold a brush or knife stroke and
even a medium stiff peak. Gel Mediums are also available in Heavy and Super
Heavy Body to help stiffen thinner viscosity paints.
• Interactive and open acrylics
were created to address the one major difference between oil and acrylic
paints, the shortened open time of acrylic paints. Designed with a retarder,
slow drying medium, or other proprietary mediums that allow the paints to be
reopened, these paints can take anywhere from a few hours to a few days, or
even a few weeks to dry completely.
• Fluid acrylics, or flow, soft
body acrylics, have a lower viscosity but generally have the same heavy
pigmentation of the heavy body acrylics. Available in either Artist quality or
Craft quality, there is a fluid acrylic for every level of art and budget.
These paints are good for watercolor techniques, airbrush application, or when
smooth coverage is desired. Mix the fluid acrylics with any of the mediums to
thicken them for impasto work or thin them for glazing applications.
• Iridescent, pearl and
interference acrylic colors combine conventional pigments with powdered
mica (aluminum) or powdered bronze to achieve complex effects. Colors have
shimmering or reflective characteristics, depending on the coarseness or
fineness of the powder. Iridescent colors are used in both fine arts and
crafts.
• Acrylic gouache is like
traditional gouache in that dries to a matte finish and is opaque. However,
unlike traditional gouache, the acrylic binder in the acrylic gouache makes it
water resistant once dry. Like craft acrylics, it will stick to a variety of
surfaces other than canvas and paper. This paint is typically used by
watercolorists, cartoonists, illustrators, and for decorative or folk art
applications.
• Exterior acrylics are
paints that can withstand outdoor conditions. Like craft acrylics, they adhere
to many surfaces. They are more resistant to both water and ultraviolet light.
This makes them the acrylic of choice for architectural murals, outdoor signs,
and many faux finishing techniques.
Differences between acrylic and oil paint
The vehicle and binder of oil
paints is linseed oil or another drying oil, whereas water serves as the
vehicle for an emulsion (suspension) of acrylic polymer that is the binder in
acrylic paint. Thus, oil paint is said to be "oil-based", while
acrylic paint is "water-based" (or sometimes
"water-borne").
The main practical difference
between most acrylics and oil paints is the inherent drying time. Oils allow
for more time to blend colors and apply even glazes over underpaintings. This
slow drying aspect of oil can be seen as an advantage for certain techniques,
but in other regards it impedes the artist trying to work quickly. The fast
evaporation of water from regular acrylic paint films can be slowed with the
use of acrylic retarders. Retarders are generally glycol or glycerin based
additives. The addition of a retarder slows the evaporation rate of the water.
Oil paints may require the use of
solvents such as mineral spirits or turpentine to thin the paint and clean up;
these generally have some level of toxicity and are often found objectionable.
(Relatively recently, water-miscible oil paints have been developed for
artists' use.) Oil paint films can become increasingly yellow and brittle with
time and lose much of their flexibility in a few decades. Additionally, the
rules of "fat over lean" must be employed to ensure the paint films
are durable.
Oil paint has a higher pigment
load than acrylic paint. As linseed oil has a smaller molecule than acrylic,
oil paint is able to absorb substantially more pigment. Oil provides a
different (less clear) refractive index than acrylic dispersions, imparting a
unique "look and feel" to the resultant paint film. Not all pigments
in oil are available in acrylic. Prussian blue has been recently added to the
acrylic colors. Acrylic paints, unlike oil, may also be fluorescent.
Due to acrylic's more flexible
nature and more consistent drying time between colors, the painter does not
have to follow the "fat over lean" rule of oil painting, where more
medium must be applied to each layer to avoid cracking. While canvas needs to
be properly sized and primed before painting with oil (otherwise it will
eventually rot the canvas), acrylic can be safely applied to raw canvas. The
rapid drying of the paint tends to discourage the blending of color and use of
wet-in-wet technique as in oil painting. While acrylic retarders can slow
drying time to several hours, it remains a relatively fast-drying medium, and
the addition of too much acrylic retarder can prevent the paint from ever
drying properly.
Meanwhile, acrylic paint is very
elastic, which prevents cracking from occurring. Acrylic paint's binder is
acrylic polymer emulsion; as this binder dries the paint remains flexible.
Another difference between oil
and acrylic paints is the versatility offered by acrylic paints - acrylic is
very useful in mixed media, allowing use of pastel (oil & chalk), charcoal,
pen, etc. on top of the dried acrylic painted surface. Mixing other bodies into
the acrylic is possible - sand, rice, even pasta may be incorporated in the
artwork. Mixing artist or student quality acrylic paint with household acrylic
emulsions is possible, allowing the use of pre-mixed tints straight from the
tube or tin, so presenting the painter with a vast color range at his or her
disposal. This versatility is also illustrated in the wide variety of
additional artistic uses that acrylics afford the artist. Specialist acrylics
have been manufactured and used for lino block printing (acrylic block printing
ink produced by Derivan since the early 1980s), face painting, airbrushing,
water color techniques, and fabric screen printing.
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