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Solvents, Oils, Mediums & Varnishes

Artists’ colours are the basic ingredients for the painter. However, the range of oils, mediums, varnishes, solvents and primers are additional ingredients from which an infinite variety of adjustments can be made to the colour, all to suit the individual creative vision of the artist.


Solvents are used to dilute the oil colour, as well as for cleaning brushes and palettes after the painting session. Solvents made for use by artists are intended to be fully volatile, meaning that upon evaporation from the paint mixture, they leave no residual matter behind. “Hardware/DIY grade” solvents, though lower in cost, are not refined to the degree required by artists, and will often leave a tacky painting surface where used, and a paint film that won’t fully dry.

English Distilled Turpentine All solvents vary in strength and in their capacity to “loosen up” the body of the colour. The artists’ grade solvent with the greatest power is English Distilled Turpentine, the only artists’ grade solvent capable of easily dissolving Dammar resin. Turpentine makes a viscous mixture, evaporates slowly, is the most hazardous and strongest smelling solvent commonly used by artists.

Artists’ White Spirit (mineral spirit) makes a watery mixture, evaporates quickly, is less hazardous, less costly, and does not deteriorate on storage.

Sansodor makes a viscous mixture, evaporates slowly, is the least hazardous, costs approximately the same as turpentine, does not deteriorate on storage, and has minimal odour.

Solvents have become generally recognized as potential health hazards. Used sensibly, however, they do not present dangers to most users.

Over the last few years, safer solvents have come to market. The new solvents have far lower aromatic content (the portion of the solvent that can be harmful). For painters that exhibit sensitivity to Turpentine, we recommend Sansodor, a very low aromatic, hydrocarbon solvent. The threshold limit value (TLV) is a measurement of how much solvent is safe within your immediate environment over a given period. The higher the number (in parts per million), the safer the product. The TLV for Sansodor is 300ppm. By contrast, the TLV for turpentine is 100ppm.

If preferring to avoid solvents altogether, Artisan Water Mixable Oils offer a genuine oil colour alternative, free from conventional solvents.

Drying Oils and Semi-Drying Oils

Drying oils and semi-drying oils are the vegetable oils used to make the colour, namely linseed, poppy and safflower. Different methods of processing produce oils with different drying rates, consistencies and colour. Drying oils are often used to modify the consistency and drying of colour in much the same way as prepared mediums.

Cold-Pressed Linseed Oil can be added to colour to reduce the consistency, improve flow, and increase gloss and transparency.

Refined Linseed Oil offers many of the same qualities as the Cold- Pressed variety, while slowing drying. It is the most popular oil.

Linseed Stand Oil improves the flow and levelling of colour. It’s well suited for glazing and for fine detail and is resistant to yellowing while increasing the durability of the film. It slows drying and is the best oil to choose as an additive medium.

Bleached Linseed Oil speeds drying, improves flow and because of its pale hue, is particularly well suited for use with light colours.

Thickened Linseed Oil speeds drying even more than Bleached Linseed Oil, improves flow and gloss and increases the durability of the film.

Drying Linseed Oil promotes the fastest drying rate of all drying oils while increasing gloss.

Drying Poppy Oil speeds drying, is resistant to yellowing and is well suited for use with light colours.


Mediums are prepared additives that alter or enhance the characteristics of the colour. They are used to change the rate of drying, increase gloss, improve flow, provide texture, etc. Mediums are prepared using the same binders and vehicles used in milling the colour: linseed oil, alkyd resin, and modified oils for water mixability. Traditional oil based mediums are made from a combination of oil and solvents, while the alkyd based mediums combine synthetic alkyd resins and solvents.

All mediums should be used in moderation; they are intended only as an additive to the colour. In addition, the artist should avoid adding multiple mediums to the colour. The most stable film is likely to contain a single medium. Because the alkyd resin functions in much the same way as a linseed oil, alkyd mediums may be added to conventional oils. Alkyd resin mediums offer dramatic advantages through accelerating the speed of drying, as well as adding a unique, natural translucency.

Liquin. Of all alkyd mediums, the most popular, world-wide, is Liquin. It speeds drying, improves flow, increases gloss, is resistant to yellowing, and is ideal for glazing.

Wingel speeds drying and improves flow and gloss while maintaining a slightly stiffer consistency than Liquin.

Oleopasto speeds drying and is ideally suited for impasto techniques.

Artists’ Painting Medium is a prepared medium that thins the colour consistency, improves flow, slows drying, increases the durability of the film and is resistant to yellowing. Artists’ Painting Medium is well suited for “oiling out”, an application of medium to a painting which has sunk, or has lost its oil to the layer below. The most common cause for sinking is through the use of a ground that is too absorbent. Winsor & Newton gessoes should always be used as a ground rather than any household primer.

Mediums for Artisan Water Mixable Oil Colours

Mediums for Artisan Water Mixable Oil Colours should be confined to use with Artisan. The mediums are made from the same modified linseed oil used in the formulation of the colour, and will offer the same characteristics as mediums by the same name intended for conventional oils. When using these mediums, always shake the bottle well before use and mix the medium thoroughly into the colour, gradually adding small amounts of water only if needed.

Artisan Water Mixable Linseed Oil reduces the consistency and improves the flow of Artisan colours. It also increases gloss and transparency.

Artisan Water Mixable Stand Oil serves to improve flow and levelling of the colour. It is excellent for glazing and producing detail as it smoothes brushwork. It is slow drying.

Artisan Water Mixable Fast Drying Medium improves the flow of colour while it speeds the drying. As it smoothes brushwork, increases gloss and transparency, it is ideally suited for glazing applications. It is resistant to yellowing.

Artisan Water Mixable Painting Medium thins the consistency of Artisan colour and aids fine detail work. It also improves flow while drying slowly. The medium is well suited to “oiling out.”

Artisan Water Mixable Impasto Medium is a texturing medium for use with Artisan. Always mix thoroughly into the colour. For thick impasto, build the texture in layers, allowing each layer to dry before applying another. This medium speeds drying.


Varnishes are essential for the protection of finished oil paintings, and they fall into two basic categories: retouch and final.

Retouching varnish may be used as a temporary varnish and to provide temporary protection for recently finished oil paintings. Paintings should be allowed to dry as long as possible (at least one month) before applying the retouching varnish. The retouching varnish does not require removal before a final varnish is applied. Paintings upon which retouching varnish has been used still require an appropriate drying period before application of the final varnish (minimum of six months for thin films, longer for thick films).

Final Varnish

In general, the ideal final varnish should:

  • Be clear and resistant to yellowing

  • Provide protection against dirt and dust

  • Bring an even sheen to the surface of the painting, and;

  • Be easily removable, or reversible, should the painting beneath need any attention, repair, restoration, or removal of dirty varnish

Oil paintings should be allowed to dry thoroughly before applying a final varnish. A painting with thin colour will dry in six months, while an impasto painting will require longer. If paintings are varnished too early, one or more of the following problems may occur:

  • The varnish will turn tacky and not dry

  • The varnish may sink into the paint film and turn the colour sensitive to solvent. Any subsequent attempt to clean in the future may well remove the painting itself

  • Matt varnishes may sink, leaving the matting agent as a white deposit upon the painting surface

  • The varnish film may crack

To determine if your painting is ready to varnish, apply a small amount of white spirit (mineral spirits) to a clean cloth. Gently rub a corner of the painting surface with the solvent-carrying rag. If no colour comes free, the painting is ready for varnishing. If colour continues to come free following an appropriate drying period, it may mean that the oil vehicle has sunk because of a ground that’s too absorbent, or that the colour was overthinned with solvent, and is subsequently underbound. The painting should be oiled out, and allowed to dry. It will then be suitable for varnishing.

Application Methods. Varnishes may be applied by brush or by aerosol spray. For a satisfactory surface finish and to minimize exposure to any solvents within the mixture, Winsor & Newton does not recommend the application of varnish by hand and rag. For convenience, Winsor & Newton offers a selection of aerosol varnishes.

Winsor & Newton makes a wide range of varnishes. Below is a listing of the qualities that can be expected from each:

Dammar Varnish is the traditional high-gloss varnish. It requires a strong solvent, like turpentine for dilution, so appropriate care is required in handling.

Artists’ Gloss Varnish & Artists’ Picture Varnish are high gloss and water white. They serve as a modern replacement for Dammar.

Conserv-Art Gloss Varnish & Conserv-Art Matt Varnish (UK: renamed Artists’ Matt Varnish) represent the very latest in varnish chemistry. The gloss variety offers the lowest gloss finish, they are water white and readily removable for over 100 years.

Wax Varnish offers the lowest, most matt finish and remains readily removable.

Aerosol Varnishes are a range including a series that are formulated for great clarity, as well as being non-yellowing and removable. The available aerosol varnishes are:

  • Artists’ Picture Varnish (in Gloss, Satin, and Matt)

  • Dammar Varnish (High Gloss)

  • Artists’ Retouching Varnish (Gloss)

These products offer the quality and benefits of Winsor & Newton artists’ quality varnishes for oils, alkyds and acrylics, but with the added convenience of an aerosol spray.

In addition, the aerosol range includes non-removable All-Purpose Varnish (Gloss and Matt) for use with acrylics and craft applications. There is also an excellent quality Artists’ Fixative for use with pastels, graphite, and charcoal.

 Click here to see our range of mediums, solvents & varnishes