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Gel & Medium Review
Gel & Molding Paste Properties / Differences Between Gels & Mediums / Size Chart /
Using Gel & Molding Paste
/ Gel Applications / Product Review / Back to Index Page

Gels & Mediums Review
Gel & Medium Differences / Product Application / Additional Suggestions /
Individual Gel Product Descriptions

Product Description
Gels and Mediums range in thickness from watery to paste-like consistencies and allow artists to manipulate their acrylic paint systems. Even though acrylic colors are offered in various different consistencies and finishes, the use of gels and mediums in conjunction with such colors broadens the working properties and expands on the possible results. GOLDEN Gels and Mediums are extremely versatile, and can be used for:

Altering Consistency
Altering Sheen
Gluing/Laminating
Increasing Film Integrity
Transparency
Cost Effectiveness
Adding Texture
Priming Supports
Paint-Making Binders

Below are some answers to commonly
asked questions about these products.

Why Are There So Many Gels and Mediums?
Over the years, artists have continuously requested new gels and mediums that behave and handle differently than those existing at the time. Golden Artist Colors has always listened very carefully to the requests of our customers. Through working directly with these professional artists, we have been able to formulate the desired products. As a result, GOLDEN is recognized as the leader in the field of gels and mediums, and has an exceptionally broad range of such products.

Admittedly, such a large number of different gels and mediums to choose from may often seem confusing to artists. However, with at least a general understanding of the various products available, and an inclination towards experimentation, artists can create new ways in which to express themselves, and probably apply materials in a way that GOLDEN has not even thought about.

What Are Gels and Mediums Made Of?
The gels and mediums can be thought of as colorless paints, as they are composed of the same polymers as GOLDEN Acrylic paints. Essentially, they are the "glue" or binder that dry to form continuous, durable films. They are made of 100% acrylic polymers, which are proven to have excellent flexibility and chemical, water and ultraviolet radiation resistance.

What Do Gels and Mediums Do?
GOLDEN offers a wide selection of gels and mediums, but this doesn't mean that each one has limited uses. Because of their very nature, most gels and mediums can function in a variety of ways, yielding numerous results. The section that follows lists the most traditional use of such products, but by no means is this intended to be an all-encompassing and exhaustive list. There are always new and different ways in which these products can be successfully applied.

Gel & Medium Differences
top / Product Application / Additional Suggestions / Individual Gel Product Descriptions

With so many products to be aware of, it becomes quite a task to keep them all straight. However, there are a few general distinctions that can make the whole group of gels and mediums seem much less difficult to understand.

Viscosity:
The main property that differentiates a majority of products is viscosity - that is, how thick or thin a product is. This is what actually separates the gels from the mediums. The mediums are thinner than the gels, which have much higher viscosities. Mediums are thin enough to be pourable, while the gels are not.

Within the gel grouping, the names reflect the scale of viscosity, and not any differences in feel of dry films. Soft Gels are thinner than Regular Gels, which are thinner than Heavy Gels, which in turn are thinner than Extra-Heavy Gels. Heavy Gels do not weigh more, and Soft Gels do not feel spongier or more flexible when dry.

Leveling Differences:
Perhaps the least understood of all paint characteristics is leveling. Leveling, also referred to as rheology, has a direct relationship to viscosity. It controls the way a paint feels and how it is best applied. This "feel" is dictated by the type of thickener used during the paint-making process.

There are two types of rheologies used in acrylic paint-making:
short and long.

Short rheology refers to the way the paint "breaks short," that is to say it imparts a buttery feel to the paint. Short rheology is used in our Soft, Regular, Heavy and Extra Heavy Gels, and is produced by the same type of thickener used in our Heavy Body line of paints. It allows paint to retain brush strokes, sometimes referred to as "memory". Soft Gels hold softer impasto peaks, and Extra Heavy Gels hold stiffer, more distinct peaks. The GAC Mediums are produced with the same thickener, but they are much thinner in viscosity and show less brush strokes than a gel does.

Long rheology, on the other hand, refers to the "syrupy" quality of certain paints, gels and mediums. These products offer better leveling and less brush strokes. GOLDEN Clear Tar Gel is the extreme long rheology product, and conceivably could be poured from a three-story building as one long strand! Polymer Medium has this property as well. Although Soft Gel and Self-Leveling Clear Gel are the same viscosity, they react much differently due to the long rheology thickener added to the Clear Gel formula. Long rheology products can be used to thicken a paint to the proper viscosity while imparting a certain leveling quality.

Reflectance:
Another key property is reflectance or sheen. This is the most important difference between Polymer Medium Gloss and Matte Medium. Nearly all the GOLDEN Gels are available in Gloss, Semi-Gloss and Matte finishes. Hence, a Heavy Gel Gloss and Heavy Gel Matte will feel very similar in consistency, but will dry with different sheens. The Semi-Gloss gels dry with an appearance similar to wax, and this aspect has been used extensively to create wax-like impressions.

Textural Qualities:
Over the years, many artists have wanted to add texture to their media. Sand, sawdust and other gritty material have been mixed with acrylic mediums. Problems arise from this, ranging from impurities causing discoloration to overloaded systems cracking and falling apart. The GOLDEN textural gels have been thoroughly researched and developed to ensure their status as archival products.

There are several products that impart a texture to the paint. Pumice Gels are composed of pumice (volcanic lava) and are ideal for creating rough, granular surfaces. Clear Granular Gel has the same textural qualities as Extra Coarse Pumice Gel, but the solids are clear acrylic, allowing for new transparent possibilities with texture. The newest gels to enter this category is the Glass Bead Gel. The texture in the Glass Bead Gel comes from genuine glass beads.

Unique Characteristics:
GOLDEN also produces specialty products that do not fit into the above differentiations. These are products that have some other unique property, requiring a different naming convention. In such cases, GOLDEN has tried to assign a name that has significance to the product's most unique feature. For instance, High Solid Gels have higher levels of polymer solids than the other gels (approximately 60%, versus 45-50%), and Light Molding Paste allows for thick films to be built up without accumulating a lot of weight.

Product Application
top / Gel & Medium Differences / Additional Suggestions / Individual Gel Product Descriptions

Getting The Most From Acrylic Paints:
One of the primary roles of gels and mediums is to extend the paint for economical reasons. One can actually create his or her own "student grade" paint by adding a gel or medium into our existing paints. For this purpose, there are basically no limitations as to minimum or maximum levels of gels or mediums that can be safely (from an archival viewpoint) added into the paint system.

Changing Paint Consistency:
Gels and mediums have also been used to alter the consistency or body of the acrylic paints. When one needs GOLDEN Heavy Body or Matte Acrylics to be thinner or to flow better, the addition of nearly any one of the Mediums or the Soft Gels will prove helpful. Better leveling and less brush strokes can be attained quickly by adding the Clear Tar Gel. When additional body is required in the Heavy Body and/or Matte Acrylics, the Heavy Gels, Extra-Heavy Gels or High Solid Gels may be added. The gels and mediums can be used with any other acrylic paint line, such as GOLDEN Fluid Acrylics, for similar purposes.

Additionally, an artist can thin paints down for spray-application. GOLDEN Airbrush Medium and Airbrush Transparent Extender both thin paint for this purpose without loss of film strength. Thinning with water only will result in a weaker overall film and an increased risk of other poor film qualities such as sagging and runs. Paint thinned with water also clogs spray equipment much more frequently.

Controlling Sheen:
The gels and mediums offer a variety of reflectance properties (Matte, Semi-Gloss and Gloss), enabling artists to control sheen in their artwork by blending the appropriate gel or medium with acrylic paints. The typical higher gloss of GOLDEN Heavy Body or Fluid Acrylics can be reduced by adding any of the matte gels or mediums. Similarly, to increase gloss of GOLDEN Matte or High Load Acrylics, the addition of a gloss gel or medium will prove effective. More subtle modifications can be created using the semi-gloss products, or a combination of a matte and gloss gel or medium.

Use as a Glue:
Gels and mediums are also frequently used as a glue for collaging materials together. This technique is valuable when collaging any materials that water-based acrylics have no difficulty bonding with. Certain materials, such as glass and certain metals and plastics, should be avoided. The Gloss products are usually preferred for this purpose, since they offer the greatest transparency; however, the other sheens work just as well as a glue. Generally, we recommend the Soft Gel Gloss for this purpose, although the choice of medium or gel can be as exacting as the artist wishes.

Increasing Film Integrity:
Because the majority of gels and mediums are nearly pure binder, they can be utilized to increase the dry film integrity of weakened systems. When an excessive amount of dry pigment or extender has been added into a paint (typically observed as cracking or chalky quality in the dry paint film), the addition of a gel or medium can correct the problem. Another weakened paint system is a paint/water blend, in which there is more water than paint. If such a mixture is to be applied on non-absorbent supports (i.e. in non-stain applications), then a gel or medium should be added so that no more than half of the entire mixture is water. Note that Gloss products work best for these sort of requirements.

Controlling Transparency:
To increase the transparency of acrylic paints, gels and mediums are useful tools. Nearly all gels and mediums are effective for this purpose, with the exception of those that are opaque (the Pumices and Molding Pastes). The Gloss Gels are most effective, especially when highly transparent glazes are desired or when the glazes are to be applied thickly (greater than 1/8 inch wet film thickness). The Matte and Semi-Gloss products will increase the translucency of the paint, but will not yield genuinely transparent glazes. This is the result of the matting agents in such products detracting from the overall transparency. Remember: the milky acrylic emulsion eventually dries translucent, and this must be kept in mind when determining the amount of color to add to the gels and mediums.

When the desired outcome is to extend the paint without increasing transparency, or specifically to increase opacity, then the addition of Molding Paste is beneficial. While there are some products available that are marketed specifically to increase opacity of paints, GOLDEN Molding Paste works equally well for this purpose. It must be understood that the addition of such products will result in a color shift to a lower chroma (and possibly lighter value) color.

Adding Dimensionality to Acrylic Paints:
A standard use of the thicker gels is to build relief, or 3-dimensionality onto the support. For this, GOLDEN Heavy Gels, Extra-Heavy Gels, High Solid Gels and Molding Pastes are valuable tools. The Light Molding Paste holds the highest peaks and retains structure, and is also the best choice when building very thick applications (least weight buildup). GOLDEN Pumice Gels are suitable when generating granular or pebbled surfaces (either 3-dimensional or flat).

Use as a Support Primer:
A final conventional application of the gels and mediums is to prime and prepare various supports. This is beneficial whenever one wants a translucent primer instead of an opaque gesso to allow the nature of the support to show through. For this purpose, the most commonly used products are the Matte Medium and GAC 100. The thicker gels can be used, but one must be careful in application to avoid holdout (the lack of adequate bonding between gel and support). Use of sufficient pressure during application, to force the gel into the tooth of the support, can overcome this problem. GAC 100 is also useful for stopping S.I.D. (See the below specific description for GAC 100).

Making Paint:
When making one's own paint from dry pigment, the various Gloss, Semi-Gloss and Matte gels or mediums serve well as the binder that forms a continuous film, encasing the pigment. The Gloss products have the greatest binding capabilities, while that of the Matte and Semi-Gloss products is somewhat reduced (the result of already containing the matting agents responsible for the lower sheen).

Additional Suggestions
top / Gel & Medium Differences / Product Application / Individual Gel Product Descriptions

Learning the Rules:
As implied from the extensive list of uses above, there is not a lot of limitation or restriction on the use of gels and mediums. An artist can mix any quantity of Gel with GOLDEN Acrylic colors, or other Gels and Mediums. However, the following are rules that should be obeyed:

  • To thin, add a thinner GOLDEN Medium or water.
  • When blending thin products into a gel, add in small portions with thorough and careful stirring at each addition.
  • For slower drying, add GOLDEN Retarder, but do not exceed 15%, as it will result in a surface that will not lose its tack. Acrylic Glazing Liquid can be used in place of straight Retarder, and there are no restrictions on amounts.
    Do not mix with oils.
  • Abrade non-absorbent surfaces for increased adhesion.
  • Minimum film formation temperature is 49oF/9oC. Avoid freezing.
  • Paint on any non-oily surface.
  • Clean tools and brushes with soap and water.

Controlling Foam:
Be aware that nearly all acrylics have a propensity to foam and get air trapped within them. This can be most dramatic when applying glazes and various translucent effects. Therefore, it is important to take proper precautions and to handle the materials carefully. This includes: avoid shaking, do not whip or stir excessively, refrain from generating a vortex during mechanical mixing and pour and handle slowly and carefully. Refer to the article in Just Paint Issue # 4, entitled "Taming the Foam Monster in Acrylic Paint," for more complete information on foam.

Drying Acrylic Films:
Drying times are influenced by many factors. The most important factors are the thickness of application and the temperature, humidity and air flow conditions in the working area. While acrylics surface dry, or skin over, very quickly (sometimes within minutes), they typically take much longer, sometimes months, to thoroughly dry. Obviously, the thicker the film, the slower it is to dry. The development of clarity in the film does not occur until the gel or medium is fairly dry. A 1/4 inch thick film of a Gloss Gel will take a week or two, even in ideal conditions (70-80oF, relative humidity of 50% or less and a moderate flow of air in drying area) to develop clarity. When humidity pushes over 80%, that same Gloss Gel may remain cloudy for several months. (For more information on drying considerations, refer to GOLDEN Information Sheet: "Technical Notes on Drying").

Stopping Support Induced Discoloration (SID):
Common supports (e.g. cotton canvas, linen, masonite) contain water-extractable materials that can cause discoloration in transparent glazes. This manifests itself as a yellow or brown tone, and is especially of concern when the glazes are thickly applied (greater than 1/16 inch wet film thickness). To minimize Support Induced Discoloration (SID), seal support with GOLDEN GAC 100 or GAC 700, followed by gesso. Note that multiple coats of gesso alone will not be sufficient to protect from SID.

True Varnishes vs. Acrylic Gels and Mediums:
One final point to make about the use of gels and mediums is that all of these products are NOT recommended as final picture varnishes. Generally speaking, these products do not have proper balance of properties for such application. They are all either too soft, too hard, or they simply foam up too much to be a clear topcoat. They also all lack the property of removability. None of the gels or mediums are removable in a manner that would not harm the underlying paint films, and this is an important consideration for final varnishes. Soft Gel Gloss, thinned 2:1 with water, on the other hand, is recommended as an "isolation coat". An isolation coat has several functions. Applied after completion of an acrylic painting, it seals the surface, lowers the absorbency of the surface, allows for a more uniform varnish application and serves to protect the acrylic paint during varnish removal. Not applying this coat can cause serious side effects, such as the varnish absorbing into a porous support. For spray application of an isolation coat, a mixture of GAC 500 (2:1) with Airbrush Transparent Extender is well suited.

(For more information on varnishing and isolation coats, refer to the GOLDEN Varnish Product & Application Guide).

Conclusion
While fully understanding gels and mediums does take time, with some experimentation and an open mind, artists can achieve painting effects that they would have never have dreamed of. There are certainly a few dos and don'ts, but there is still a great degree of freedom on the use of each member of this grouping, with each able to be used in a broad range of applications and techniques. It is important to remember that the applications that we as manufacturers have suggested for these products are simply starting points. Through each artist's own unique vision, the gels and mediums will continue to be utilized in new and exciting ways, to create effects that we would have never imagined possible.

Individual Golden Gel Product Descriptions
Top / Gel & Medium Differences / Product Application / Additional Suggestions

Clear Tar Gel
This product is the extreme in leveling. It is designed to produce an even film with excellent clarity. The gel has a unique resinous, stringy consistency and dries to a flexible, high gloss film.

Clear Tar Gel can be used increase transparency and sheen while imparting a leveling quality to other GOLDEN Acrylic products. Excellent for dripping, drizzling effects that no other product will yield. Blends with all GOLDEN Acrylic colors (though Fluids work best) offering a full range of colors for these techniques.

Self-Leveling Clear Gel
Designed to produce an even film with excellent clarity. This gel has similar qualities to the Clear Tar Gel: it has a resinous consistency and offers excellent leveling, yet its viscosity is closer to that of the Soft Gel. This product dries to a flexible, high gloss film, which can increase transparency and sheen while imparting a leveling quality to other GOLDEN Acrylic products. Blends with GOLDEN Acrylic colors to produce glazes without brush-strokes.

Soft Gel (Gloss, Matte and Semi-Gloss)
Thinner than GOLDEN Heavy Body Acrylic colors, Soft Gels are moderately pourable and hold only slight peaks.

Soft Gel Gloss is ideal for glazing and other techniques where transparency is desired. Also, the recommended acrylic to function as a glue for collaging. Useful as a non-removable isolation coat, applied over the painting before the varnish layer (must be thinned with water - 2 parts Soft Gel Gloss to 1 parts water).

Regular Gel (Gloss, Matte and Semi-Gloss)
Same creamy consistency as GOLDEN Heavy Body Acrylic colors. Ideal for extending paint and regulating translucency without changing the consistency of the Heavy Body and Matte colors. Holds moderate peaks and texture. The Regular Gel Gloss is ideal for glazing and other techniques where transparency is desired.

Heavy Gel (Gloss, Matte and Semi-Gloss)
Thicker consistency than GOLDEN Heavy Body Acrylic colors. Blend with colors to increase body. Good for holding peaks. Dries translucent.

Extra Heavy Gel (Gloss, Matte & Semi-Gloss)
Thicker consistency than GOLDEN Heavy Body Acrylic colors. GOLDEN's thickest gels, along with the High Solid Gels. Blend with colors to increase body. Excellent for holding peaks and impasto techniques. Dries translucent.

High Solid Gel (Gloss)
Thicker consistency than GOLDEN Heavy Body Acrylic colors, similar to Extra Heavy Gels. Offers higher gloss, lower shrinkage and dries to the touch quicker than most Gels. Good for holding peaks. Blends with colors to make them feel more oil-like and increases retention of brushstrokes.

High Solid Gel (Matte)
Thicker consistency than GOLDEN Heavy Body Acrylic colors, similar to Extra Heavy Gels. Dries to a matte finish. Offers lower shrinkage and dries to touch quicker than most Gels. Good for holding peaks. Blends with colors to make them feel more oil-like and increases retention of brushstrokes.

Fine Pumice Gel
Used to create finely textured surfaces. Dries to a hard film. To increase flexibility, mix in other GOLDEN Gels or Mediums. Blends with GOLDEN Acrylic colors. Useful as a ground for pastels.

Coarse Pumice Gel
Used to create granular textured surfaces. Dries to a hard film. To increase flexibility, mix in other GOLDEN Gels or Mediums. Blends with GOLDEN Acrylic colors. Useful as a ground for pastels.

Extra Coarse Pumice Gel
Used to create granular textured surfaces. Dries to a hard film. To increase its flexibility, mix in other GOLDEN Gels or Mediums. Blends with GOLDEN Acrylic colors.

Glass Bead Gel
A coarse textured medium with a Heavy Body viscosity that holds peaks. Made with genuine glass beads, its unique visual effect – like that of condensation on cold glass – is best seen in thin films that allow the mono-layer of glass beads to be illuminated on a light colored ground. Glass Bead Gel can appear very similar to Coarse Pumice Gel or Clear Granular Gel when mixed with enough paint to hide the appearance of the glass beads.

Clear Granular Gel
The same textural quality as its pumice counterpart, without the gray, opaque grit. Excellent for making translucent, textural glazes. The chroma will not be affected. Blends with GOLDEN Acrylics.

Glass Bead Gel
A coarse textured medium with a Heavy Body viscosity that holds peaks. Made with genuine glass beads, its unique visual effect -- like that of condensation on cold glass -- is best seen in thin films that allow the mono-layer of glass beads to be illuminated on a light colored ground. Glass Bead Gel can appear very similar to Coarse Pumice Gel or Clear Granular Gel when mixed with enough paint to hide the appearance of the glass beads.

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