Oil Painting Mediums Demystified
To Oil or not to Oil
Approaching oil painting is often met with trepidation by new and experienced artists alike. Perhaps you have worked in acrylic for a number of years and are considering the switch to oil, or maybe you have no experience painting at all but love the work of famous masters whose medium of choice was oil. Whatever your background, learning how to paint in oils can be equally attractive and daunting.
Part of the reason for this is the intimidating quantity of products on the market, often sold with little to no accompanying information on use. Knowing the right medium to use is really about your intended look - what is the right medium for you?
Being totally new to oil painting can be a gift. If you have little to no prior experience with any kind of painting mediums, you are free to experiment without preconceived notions. What matters is that you find an individual system that works.
Let's see what oil mediums can do.
The general purpose of any medium used for oil painting is to thin or extend the paint and control drying time. There is the option to not use any type of medium, but you will that find your paint is harder to control and diminishing at a startling rate. This technique is not recommended.
Traditionally, artists used turpentine or linseed oil, or a specific formula of resins combining both. In recent decades, turpentine has become less popular, most likely because of its toxicity and difficulty of disposal. Linseed oil has endured, still one of the most popular to this day. Other options include poppy and walnut oil (more about oil later), alkyd mediums, gels and mineral spirits.
The rule of thumb when it comes to oil painting, and mixing oil painting mediums, is "fat over lean." Because "fat" paint, or paint with a high oil content, dries significantly slower than "lean" paint (paint with low oil content), it is imperative that an artist always paints fat over lean to ensure a stable surface. Ignoring this rule will result in cracking in the paint surface as the painting dries.
While all linseed oil is clear and light yellow in color, there are actually three types that have distinguishing properties. Cold-pressed linseed oil is made from the pressing of flax seed without the help of chemical additives or procedures. It is usually one of the cheaper options; however, has the tendency to yellow over time. Refined linseed is a purer, higher quality linseed oil that will not yellow but is more expensive as a result. Stand oil is the final option when it comes to linseed. Made using a heating process, it is slightly thicker and allows for a smoother application, diminishing the appearance of brush strokes when compared to its linseed counterparts. It will exhibit little yellowing over time.
Poppy oil is one of the lesser used oils, however it can be found in most art supply stores. It is a clear oil that is especially useful for "wet on wet" techniques. Like linseed, it will increase drying time.
Walnut oil can be used interchangeably with linseed oil. It has a very similar viscosity to linseed, but shows less yellowing and cracking over time. Some paints (M. Graham, for example) are formulated with walnut oil, thus using walnut oil over linseed oil as a medium makes sense in this situation.
In addition to drying oils, there is an array of alkyd mediums on the market. Alkyd mediums are a relatively new product that are petroleum based and formulated to achieve unique effects.
Galkyd, a product made by the company Gamblin, is an easy to find option whose properties cross over into other basic alkyd mediums. Galkyd will cause paints to dry significantly faster and will create a glossy finish. Because of the decreased drying time, it is a good option if you are accustomed to working with acrylics (which dry very quickly) and are seeking an easier transition into oil.
Gamblin also offers Galkyd Lite, which is more fluid and less glossy than regular Galkyd, and Galkyd Slow Dry, a useful product if you want extended time to work wet into wet but maintain a glossy, unified surface.
All alkyd mediums work great for glazing techniques.
And yet there are even more options to consider:
Neo Megilp (Gamblin)
- A contemporary version of the historical medium Maroger (an emulsion of linseed oil, resin and other components)
- Soft, gel-like consistency that will make paints feel buttery smooth
- Moderate drying time, colors will dry to a satin finish
Galkyd Gel (Gamblin)
- Stiffer, heavier bodied gel medium, useful for impasto technique (thick application)
- Dries more quickly than Neo Megilp
- Maintains sharp brush strokes
Cold Wax Medium
- Dries to a matte finish
- Requires a more rigid support to avoid cracking
- Can also be used as a final, matte varnish
Mineral Spirits / Turpentine Substitutes
In recent years there has been an increase of products on the market for artists seeking to replace turpentine in the studio. Most of these mediums can be used to clean palettes, brushes and palette knives in addition to being used as paint thinner.
Odorless Mineral Spirits (OMS) is a petroleum distillate solvent formulated specifically for oil painters. It very thin, almost of a very light oily consistency, has no smell and can effectively be used to thin paint using only a small amount. Many oil painters use a formula of about one part linseed oil to one part OMS as their medium of choice.
Turpenoid is a product that is thin, colorless and offers the same drying time as traditional turpentine. It is more volatile than OMS but more effective as a brush cleaner. Turpenoid Natural is a similar product that boasts organic ingredients that are non-toxic and non-flammable.
Turpentine is still available in the art supply market, however there are so many newer and better substitutes that using it is thought to be unnecessary unless you are following particular traditional methods.
Being familiar with the possibilities that different oil mediums offer is imperative in getting the results you desire. The more you experiment and learn what works, the closer you are to creating a masterpiece.
Luckily, the modern market for art supplies shows no shortage of options for the contemporary painter.