A guide to oil painting mediums and techniques

Author: Dana McGorlick-Appelman  Date Posted:27 April 2021 

Oil paints have been the medium of choice for many artists for hundreds of years. Nowadays, there a vast a variety of oil painting mediums, allowing a wide variety of techniques and aesthetics to be possible. It is important to consider the results you would like to achieve when choosing a medium, as subtle differences can have a significant impact.
Keep reading to discover the various oil painting techniques and how to choose the right oil medium for your masterpiece.

OIL PAINTING TECHNIQUES

To avoid your paint cracking, there are a few rules to follow:

FAT OVER LEAN: 

The more oil in the paint, the “fatter” it is and the longer it will take to dry. To avoid cracking, make sure the lower layers of your artwork are leaner and the top layers are oilier. To prevent cracking, use lean first and fat for subsequent layers. This will give an even tension throughout the painting. This method is known as ‘lean to fat’.

THICK OVER THIN: 

Make sure that the top layers of paint are also thicker than the base layers, as thicker/high viscosity paint applications will also take longer to dry than thinner/low viscosity ones. You can thin oil paints with odourless solvent or turpentine.

GLAZING:

Glazes are thin, transparent layers of paint. Glazes are used over paint layers to build depth and add colour in a painting. A glaze must be completely dry before another is applied on top. Several mediums can be used for glazing. A glaze layer should contain at least 10% oil colour.

TYPES OF MEDIUMS

OILS

Oil can be added to Oil Paints to increase the flow and transparency of the paint, while also slowing down the drying process.

Safflower Oil

Safflower Oil is a mid-viscosity medium that can be added to Oil Paint to improve the transparency, flow and gloss of the paint, while resisting yellowing and slowing drying time. Safflower Oil is great for use with all oil colours and is particularly well suited to white and pale hues which can sometimes be more prone to yellowing.

Refined Linseed Oil

Refined Linseed Oil is the palest of linseed oils that increases the flow and slows the drying times of oil colours. Use sparingly or mix with an equal amount of a solvent such as Gamsol to create a traditional, slow-drying, low-viscosity painting medium.

Cold Pressed Linseed Oil

Cold Pressed Linseed Oil is a more traditional oil that will slow drying time and increase yellowing. Use sparingly or mix with an equal amount of a odourless solvent such as Gamsol to create a traditional slow-drying, low-viscosity painting medium.

Stand Oil

Stand Oil is a thickened version of Refined Linseed Oil that increases flow and gloss and slows dry time. Colours mixed with Stand Oil will dry to a smooth, enamel-like finish with a tough elastic film. Use sparingly or mix with an equal amount of a solvent such as Gamsol to create a traditional, slow drying, high-viscosity painting medium.

Poppy Oil

Poppy Oil is the slowest-drying oil. It is useful to painters working in traditional, wet-into-wet techniques that want the longest possible working time. Use sparingly or mix with an equal amount of solvent to create a traditional slow-drying, low-viscosity painting medium.

SOLVENTS

Solvents are ideal for use when preparing to paint, thinning oil colours and painting mediums, cleaning art supplies and removing other mediums.

Pure Gum Turpentine

Pure Gum Turpentine is a natural, double-distilled solvent for oil painting. It can be used to help prepare your art supplies for use or it can be used as a medium. 

Artists Turpentine

Turpentine is used in the preparation of painting mediums and for cleaning equipment. It has less tack than Gum Turpentine.

Gamblin Gamsol

Gamsol is a safe, non-toxic odourless alternative to turpentine and can be used to thin oil colours and painting mediums, and for general studio clean-up. All the harmful aromatic solvents have been removed and is regarded as a non-hazardous material. 

 

 LOW VISCOSITY MEDIUMS

Low viscosity (thin) fluid mediums increase the flow of oil colours, and make very thin glazes, which are used for the very first layers of paint. Consider Gamblin Solvent-free fluid or 50% refined linseed oil with 50% Gamsol for making the thinnest glaze layers.

Lean Medium is a fast-drying liquid medium used to reduce paint viscosity. By altering the body of the paint, it creates better glide and spreadability making it ideal for underpainting and thinner paint techniques. Its fast-drying properties make it the perfect medium for layering techniques and fast workability. By increasing paint transparency, it creates a gloss-like finish making it ideal for glazing. 

Art Spectrum Painting Medium No.1 is the leanest thinning medium in Art Spectrum’s sequence of four oil painting mediums. It is the fastest drying, is excellent for underpainting and colour washes, improves the adhesion of oil paint, and reduces the absorption of acrylic primed surfaces. 

Winsor & Newton 75ml - Oil Blending & Glazing Medium slows down drying time and improves paint flow making it ideal for techniques like blending, glazing, stroke work, antiquing and staining. It’s great for painting transparent layers of colour, blending colours and staining. It will leave you with a smooth, even surface with minimal brush stroke retention. 

 

HIGH VISCOSITY MEDIUMS

High viscosity (thick) fluid mediums make thicker glaze layers compared to low viscosity mediums, levelling brush marks and creating an enamel-like surface. High viscosity painting mediums increase the flow of oil colours and self-level brush marks, yet impart a “sticky”, quality. Consider Fat Medium, Art Spectrum Painting Medium No.2 and No. 3, Gamblin Galkyd and Stand Oil for this.

Fat Medium is thicker, oilier and slower drying medium that should be mixed with oils and applied as the final medium in the "fat over lean" sequence.

Art Spectrum Painting Medium No.2 is a great general oil painting medium, but also fantastic when used in the ‘fat over lean’ oil painting sequence following Art Spectrum No.1 Medium, being fatter and slower drying. Art Spectrum Painting Medium No.3 is even thicker, oilier and slower drying than Art Spectrum No.1 and No.2 Mediums, and can be used as the final medium in the 'fat over lean' oil painting sequence.  On its own, it can also be used as a general oil painting medium and levelling agent.

Gamblin Galkyd is another great oil medium that when used in greater proportions with oil colour, will also level brushstrokes, creating an enamel-like surface while being fast drying.

CREATING FINE DETAIL

To create fine detail work and greater blending capabilities with your oil painting, the Winsor & Newton Liquin Original is a great pale-yellow thinning medium for oil, which is designed to improve flow and wetting. This reliable favourite is a general-purpose semi-gloss medium which speeds drying, improves flow and reduces brush stroke retention and resists yellowing. 

The Winsor & Newton Liquin Fine Detail is a more fluid quick-drying, high-gloss medium that can also be used for fine detail, glazing, blending or to produce a smooth surface to your works, removing brush strokes and texture. It speeds up paint drying time with a touch-dry finish in rapid time. It resists yellowing, maintaining colour and brightness of paint over time. It is a natural approach to paint thinning and avoids the use of harsh chemicals.

The Art Spectrum Painting Medium No.4 (Liquol) is another great fast-drying, free-flowing, self-levelling medium for oils, excellent for thin glazing, transparent painting, blending and extending brush detail.