Choosing and Using Acrylic Mediums - by Greg Kimsey
When you venture into the Acrylic Mediums aisle at the Art-Full Barn you may be a bit overwhelmed at the myriad of selections offered. It can be difficult to know which medium to use. Hopefully this ART-Tickle will help you understand what they do and what you need. I will deal mostly with Liquitex and Golden mediums since those are the two main brands we offer at The Art-Full Barn. Other brands such as Winsor & Newton, Daler Rowney, Grumbacher, etc, work just as well and perform similarly.
The beauty of acrylic paints is their versatility. They can be used straight from the tube and thick for an oil paint look, or may be thinned greatly for a watercolor painting look, or may be used by combining techniques for a uniquely Acrylic look. Acrylic paints use the same pigments as oils and watercolors, but use an Acrylic Binder Emulsion as the vehicle. Most acrylic mediums are made with the same Acrylic Emulsion found in the tube of paint, therefore may be used to extend the paint at a much lower cost to the artist. Acrylic mediums will do one or more of several different things to your paint; either make it thicker or thinner, more or less glossy, and may or may not affect the drying rate. Another neat thing offered by using mediums is the chance to add different textures to your paint. Mixing stuff like sand or other items into the emulsion can create really interesting effects. You may ask, "Can't I just use water to thin the paint?" Yes you can, and many people do. Doing so will dilute the pigment and make it much more transparent as well as more matte. Using water alone can give a beautiful watercolor affect, which is one of the reasons acrylic paints are so versatile. Using Gel Mediums, though, will not alter the binding agents in the emulsion like water will. The Acrylic Emulsion is what binds the pigment to the substrate.
Gel Mediums: Gel mediums are the bread and butter of Acrylic Mediums. They are thickened Acrylic Emulsion and are the exact same stuff that is in the tube of paint, so Gel Medium is basically clear paint. It comes in various viscosities (thickness).
There are a few things to remember about Gels.
On to Glazing Mediums. These mediums may be called by different names and the label needs to be read to know exactly what it does. They may be called Glazing Medium, Acrylic Medium & Varnish, Slow-Dry, or Fluid Medium and most will come in Gloss, Semi-Gloss and Matte versions. Use the gloss version for the most light transfer. Some brands, such as Liquitex Glazing Medium will speed the drying time to allow you to continue layering glazes quickly. Both Liquitex Slow-Dri and Golden Glazing Medium slow the drying rate to allow extended blending right on the canvas and do not alter the surface adhesion properties of the acrylic paint. Glazes are generally used over more opaque applications to change the hue, value, and luminosity of the previous layers, while allowing those layers to show through. Mixing less paint into the medium will of course make it more transparent.
All Gels and Fluid or Glazing mediums may be used by themselves between layers of paint to create a thin or thick film for light to pass through and refract off of the lower layers creating a luminous look. They may also be used to create a non-removable protective barrier for the paint surface. However, do not use Acrylic Medium & Varnish as a "final" final varnish. Allow the acrylic painting to cure completely for one week, then varnish with a removable spirit based artist grade varnish. The reason you want to use a spirit or solvent based final varnish is that it may be removed in the future for cleaning and replacement; an acrylic final varnish may be discolored by dirt, smoke or other contaminants and unfortunately cannot be removed without damaging the actual paint layers. Both Golden and Liquitex make suitable removable solvent based varnishes for acrylic paintings. Varnishes for Oil paintings may also be used.
Flow aids: Liquitex Flow Aid and Golden Acrylic Flow Release both increase the absorption and reduce the tension or surface adhesion of acrylic color. Therefore, this medium is not to be used in great amounts when using a non absorbant substrate as it will not adhere properly. It is a wonderful medium to use on canvas or paper as it will create beautiful stain-like colors. Liquitex and Golden flow aids are strong mediums and should not be used straight out of the bottle; however, there are certain premixed brands (Deco Art comes to mind...READ the label first). Most flow aids must be thinned at minimum to one (1) part medium to ten (10) parts water. One to 20 parts water is recommended to create normal "Flow Water". Mix this in a handy squirt bottle or other jar and label the mixture ratio. For hard substrates the ratio should be no more than 3% medium or the paint won't adhere. This 1 to 20 (or 10 min) part medium may be added directly to the paint, or may be used to pre-wet the absorbant surface. When the surface is pre-wet the edges of the color will be very soft and faded. When mixed directly into the paint then applied on dry paper or canvas the edges will tend to be more distinct and "hard". To avoid foaming, handle the medium carefully and do not over shake. Stir to mix.
Texture Mediums: Liquitex and Golden both offer mediums with different solids added for various textures. Sand, beads, string, pumice, flakes, and the list goes on, may be used to create certain looks in your painting. These mediums may also be used beneath other art mediums such as oil, acrylic, pastel, oil pastel, charcoal, etc. Acrylic paint may also be added to the mediums to tone the surface for other colors to be layered on top. These can create very exciting, 3-D looks and remain flexible once dry.
Pastes: Some mediums such as Light Molding paste, Regular Molding paste, Hard Molding paste and Extra Heavy Molding paste are opaque mediums that once dry, may be carved or sanded with hand or power tools. They can also be molded while still wet and pushed around with the same tools mentioned earlier. Hard paste can be inflexible once dry and should be used on hard surfaces. It can be made more flexible by adding softer gels, and/or applying in thin layers. Applications more than 1/4" thick at a time take a long time to dry and may crack. Be sure to read the label carefully or consult with your art supply provider to know exactly what you are getting. They are used to prepare the surface for impasto looks and can be layered to great depths and thicknesses. Color can be mixed into the paste just like with gels, but will dry to an opaque finish.
A few final words: Why are there so many choices? WHO KNOWS!? The need (or more accurately, the "want") is out there or there wouldn't be so many. Having said that, I'll say this, "You don't have to use any mediums!" However, Mediums will make your paint go further, saving you money in the long run. They may also be used to create special effects. Or they may not be used at all. It's totally your choice. I will go on record and recommend two mediums, Regular Gloss Gel Medium along with either Liquitex Slow-Dri or Golden Glazing Medium. If you want to use any mediums at all with acrylics, start with these or their equivalents. If you like to paint thick impasto, then use a heavier gel instead of 'regular'; but those two mediums will be beneficial to you and make your painting life easier. Now get out those brushes and HAVE FUN!
The beauty of acrylic paints is their versatility. They can be used straight from the tube and thick for an oil paint look, or may be thinned greatly for a watercolor painting look, or may be used by combining techniques for a uniquely Acrylic look. Acrylic paints use the same pigments as oils and watercolors, but use an Acrylic Binder Emulsion as the vehicle. Most acrylic mediums are made with the same Acrylic Emulsion found in the tube of paint, therefore may be used to extend the paint at a much lower cost to the artist. Acrylic mediums will do one or more of several different things to your paint; either make it thicker or thinner, more or less glossy, and may or may not affect the drying rate. Another neat thing offered by using mediums is the chance to add different textures to your paint. Mixing stuff like sand or other items into the emulsion can create really interesting effects. You may ask, "Can't I just use water to thin the paint?" Yes you can, and many people do. Doing so will dilute the pigment and make it much more transparent as well as more matte. Using water alone can give a beautiful watercolor affect, which is one of the reasons acrylic paints are so versatile. Using Gel Mediums, though, will not alter the binding agents in the emulsion like water will. The Acrylic Emulsion is what binds the pigment to the substrate.
Gel Mediums: Gel mediums are the bread and butter of Acrylic Mediums. They are thickened Acrylic Emulsion and are the exact same stuff that is in the tube of paint, so Gel Medium is basically clear paint. It comes in various viscosities (thickness).
- Soft Gel: Is not actually "soft" once it dries so it is sort of a misnomer. It simply means it is a more fluid gel with a consistency closer to cream. It will not hold brush stroke peaks and will "level out".
- Regular Gel: The exact consistency of Heavy Body tube paint. Adding Regular Gel will not affect how the paint handles, but will extend the paint very well, and if used correctly, may not affect the colors intensity, hue, or value. It will hold visual brush strokes but with very little peak just like Heavy Body paint from the tube.
- Heavy Gel: Thicker than Heavy Body Paint, and will allow the paint to hold peaks for an impasto look.
- Extra Heavy Gel: Very thick and almost a paste. Will hold extremely high peaks for an almost 3-D effect.
There are a few things to remember about Gels.
- Don't add too much water. Adding water to a heavy gel will not make it a soft gel, and will weaken the acrylic binders instead. Purchase the viscosity you desire.
- If beads, grit, or other substances are added, make sure there is enough coating on each solid to provide proper adhesion. Do not add water if adding solids. Be sure to mix well for a complete coating.
- Don't overwork a gel medium. Once the medium becomes tacky on the substrate it's time to stop moving it around to avoid "crazing'' or cracking.
On to Glazing Mediums. These mediums may be called by different names and the label needs to be read to know exactly what it does. They may be called Glazing Medium, Acrylic Medium & Varnish, Slow-Dry, or Fluid Medium and most will come in Gloss, Semi-Gloss and Matte versions. Use the gloss version for the most light transfer. Some brands, such as Liquitex Glazing Medium will speed the drying time to allow you to continue layering glazes quickly. Both Liquitex Slow-Dri and Golden Glazing Medium slow the drying rate to allow extended blending right on the canvas and do not alter the surface adhesion properties of the acrylic paint. Glazes are generally used over more opaque applications to change the hue, value, and luminosity of the previous layers, while allowing those layers to show through. Mixing less paint into the medium will of course make it more transparent.
All Gels and Fluid or Glazing mediums may be used by themselves between layers of paint to create a thin or thick film for light to pass through and refract off of the lower layers creating a luminous look. They may also be used to create a non-removable protective barrier for the paint surface. However, do not use Acrylic Medium & Varnish as a "final" final varnish. Allow the acrylic painting to cure completely for one week, then varnish with a removable spirit based artist grade varnish. The reason you want to use a spirit or solvent based final varnish is that it may be removed in the future for cleaning and replacement; an acrylic final varnish may be discolored by dirt, smoke or other contaminants and unfortunately cannot be removed without damaging the actual paint layers. Both Golden and Liquitex make suitable removable solvent based varnishes for acrylic paintings. Varnishes for Oil paintings may also be used.
Flow aids: Liquitex Flow Aid and Golden Acrylic Flow Release both increase the absorption and reduce the tension or surface adhesion of acrylic color. Therefore, this medium is not to be used in great amounts when using a non absorbant substrate as it will not adhere properly. It is a wonderful medium to use on canvas or paper as it will create beautiful stain-like colors. Liquitex and Golden flow aids are strong mediums and should not be used straight out of the bottle; however, there are certain premixed brands (Deco Art comes to mind...READ the label first). Most flow aids must be thinned at minimum to one (1) part medium to ten (10) parts water. One to 20 parts water is recommended to create normal "Flow Water". Mix this in a handy squirt bottle or other jar and label the mixture ratio. For hard substrates the ratio should be no more than 3% medium or the paint won't adhere. This 1 to 20 (or 10 min) part medium may be added directly to the paint, or may be used to pre-wet the absorbant surface. When the surface is pre-wet the edges of the color will be very soft and faded. When mixed directly into the paint then applied on dry paper or canvas the edges will tend to be more distinct and "hard". To avoid foaming, handle the medium carefully and do not over shake. Stir to mix.
Texture Mediums: Liquitex and Golden both offer mediums with different solids added for various textures. Sand, beads, string, pumice, flakes, and the list goes on, may be used to create certain looks in your painting. These mediums may also be used beneath other art mediums such as oil, acrylic, pastel, oil pastel, charcoal, etc. Acrylic paint may also be added to the mediums to tone the surface for other colors to be layered on top. These can create very exciting, 3-D looks and remain flexible once dry.
Pastes: Some mediums such as Light Molding paste, Regular Molding paste, Hard Molding paste and Extra Heavy Molding paste are opaque mediums that once dry, may be carved or sanded with hand or power tools. They can also be molded while still wet and pushed around with the same tools mentioned earlier. Hard paste can be inflexible once dry and should be used on hard surfaces. It can be made more flexible by adding softer gels, and/or applying in thin layers. Applications more than 1/4" thick at a time take a long time to dry and may crack. Be sure to read the label carefully or consult with your art supply provider to know exactly what you are getting. They are used to prepare the surface for impasto looks and can be layered to great depths and thicknesses. Color can be mixed into the paste just like with gels, but will dry to an opaque finish.
A few final words: Why are there so many choices? WHO KNOWS!? The need (or more accurately, the "want") is out there or there wouldn't be so many. Having said that, I'll say this, "You don't have to use any mediums!" However, Mediums will make your paint go further, saving you money in the long run. They may also be used to create special effects. Or they may not be used at all. It's totally your choice. I will go on record and recommend two mediums, Regular Gloss Gel Medium along with either Liquitex Slow-Dri or Golden Glazing Medium. If you want to use any mediums at all with acrylics, start with these or their equivalents. If you like to paint thick impasto, then use a heavier gel instead of 'regular'; but those two mediums will be beneficial to you and make your painting life easier. Now get out those brushes and HAVE FUN!