Acrylic paints are a relatively new product in the world of fine art materials. Where oil paints and watercolors have been available for centuries, acrylics have only been widely sold since 1956.
Just like any painting medium, acrylics are comprised of: Vehicle plus Pigment
In acrylics, the vehicle (or binder) is acrylic polymer emulsion, acrylic particles suspended in water. Acrylic emulsion is what gives acrylics their flow and rapid drying time, sometimes as quickly as 30 minutes. Quick drying paint may be important, in school and craft applications, for example. Conversely, others may not like a paint that doesn’t allow much reworking. Oil paints might be a better choice instead.
Another important advantage to acrylic paints is their ease of clean up. Both the palette and brushes can be cleaned with soap and water, and dried palettes can be scraped with a razor blade.
Note: Do not let brushes used for acrylics dry before cleaning. Otherwise, the paint will not be removable. Also, use only non-porous materials for acrylic palettes, as wood and other porous materials will stain.
Pigment Particulars/Palette Preferences
As the pigments found in acrylics are virtually the same as those found in oil paints, and have the same opacity and mixability characteristics, please refer to Artist’s Studio Education: Oil Paint Basics for pigment information as well as a suggested beginning palette.
Making the Grade
Where the grades of oil colors are differentiated more by pigment load and the presence or absence of extenders, acrylics are classified more by:
Viscosity or thickness
Acrylics can be classified as:
High Viscosity – Tube Color
Medium Viscosity or Flow Formula – Jar Color
High viscosity makes a paint thick and buttery, like an artist’s oil color, allowing for more oil-like painting techniques (impasto, visible brush marks, etc.) High Viscosity paints are usually sold in tubes
Medium Viscosity is runnier, like a poster paint or tempera. This allows flatter, more watercolor-like painting. Medium Viscosity paints are usually sold in squeeze bottles.
But what does all this mean? How does viscosity affect the paint?
High Viscosity Acrylics act like oil paints in:
Thick Body
Showing Brush Marks
Opacity
Building Up (Impasto)
Medium Viscosity Acrylics act like watercolors in:
Thinner Body
Laying Flat on the Surface
Translucency when Thinned with Water or Medium
All Acrylics:
Are Water Soluble When Wet
Are Water Resistant When Dry
Dry Quickly
Well Done Acrylic Mediums!
Just as with oil and watercolor, acrylic’s properties can be changed, enhanced and altered thru the use of Mediums.
Mediums will:
Retard Drying – to allow longer re-working time
Slow-dri Extender
Retarder
Add Body/Reduce Flow – to create heaver, more textured paint films
Gel Medium
Impasto Medium
Texture Gel
Modeling Paste
Reduce Body/Increase Flow - to create thinner, more translucent paint films
Flow Improver
Flow Aid
Marbling/Airbrush/Fabric Mediums
Change Surface Reflectivity – to make more gloss or matt
Gloss or Matt Mediums
Gloss or Matt Varnishes
Protect the Dried Paint Film
Gloss or Matt Varnishes
Varnish Remover
Prep the Surface Before Painting
Gesso
Features and Benefits of Acrylics and Mediums:
Items | Features | Benefits |
High Viscosity | Thick and buttery | Shows brush marks, like oils |
Allows for impasto, like oils |
Medium Viscosity | Thin and runny | Allows for thin washes, like watercolors |
Creates a smooth, flat paint film when dry |
Acrylic Emulsion Vehicle | Water Soluble | Cleans with soap and water while wet, for easier care |
Thins with water to make a translucent wash, watecolor-like |
Evaporates vs. Oxidizes | Quick drying, paintings are finished more quickly |
Flexible | Crack resistant paint film when dry, more durable than oils |
Texture Gels | Contain bits of flint, sand, glass, etc | Allows artist to change texture of paint, 3D effects |
Gloss/Mat Medium | Changes reflectivity | Allows for a wide range of gloss-to-mat effects |
Flow Medium | Thins paint | Easier washes and glazes |
Modeling Paste | Air Dries | Ease of use in making models |
Drillable, sandable when dry | Easy to sculpt |
Mixes with acrylics | Makes colored models |
Makes heavy textures in paintings |
High Quality Pigments | Same as oils | Good mixability and lightfastness |
Retarder | Slows drying | Keeps acrylic paint workable longer on the surface |
Gel Medium | Thickens paint | Moderate brush work and impasto effects, between Impasto Medium and Modeling Paste |
Gloss or Mat Varnish | Protects | Keeps dust from embedding in surface |
Changes surface texture | Allows for gloss or mat effects |
Easily removed | Makes cleaning and re-varnishing easier |
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Glossary
Acrylic Polymer Vehicle | The vehicle that carries the pigment in Acrylic Colors. |
Flow | The thickness or viscosity of a paint. Some paints are formulated to be thicker and more buttery, or have a lower flow. Others are formulated to be thinner and more runny, or have a higher flow. |
Gel Medium | A moderately dense medium that increases brush marks and impasto. Density between Impasto Gel and Modeling Paste.
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Gesso | An acrylic-based ground that is applied to canvas or board before painting. A primer. |
Impasto | A painting technique that creates thick heavily textured layers of paint with obvious brush strokes. |
Mediums | A group of products that enhance workability of acrylics, or are used to clean, thin, or change the texture of a completed piece. |
Mixability | The quality with which two paints can be combined to create a third. True Pigments have better mixability than do Hues. |
Modeling Paste | A very dense medium used for sculpting and for very heavy textures in paintings |
Opacity | Denotes how much or little of the painting surface will show thru a layer of paint. True pigments tend to be more opaque, where Hues tend to be more translucent. |
Paint Film | The layer of applied paint on a ground, after it has oxidized. |
Palette | Either a selection of colors used by an artist, or the board on which those colors are placed when painting. |
Retarder | Slows drying of acrylics |
Texture Gel | Changes the texture of acrylics: beads, sand, etc. |
Varnish | A coating applied over the surface of an acrylic painting, which protects from dust and fading. A varnish must be applied after an acrylic painting is dry, at most a couple of days. |
Vehicle | The material in which a pigment is suspended in paint. Acrylics use acrylic polymer as their vehicle. |
