- Basics of oil painting: Mediums Part 3. Solvents
- Basics of oil painting: Mediums Part 2. Oils
- Basics of oil painting: Mediums Part 1
There are a lot of discussion about using the varnishes in oil painting and many opposite opinions. Some artists avoid using the varnish as a medium, some - avoid it completely. But before making the decision you need to know the details.
Firstly, varnish is resin dissolved in turpentine or in a mixture of turpentine and a drying oil such as linseed oil.
There are several types of varnishes depending on their use:
1) Retouching varnish
2) Varnishes that can be used as mediums
3) Finishing varnishes
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| Retouching varnishes by different manufacturers. I use the one by Talens (in the middle) |
1) Retouching varnish is perfect for eliminating the dullness. I have a post about the causes of dullness here - Basics of oil painting: What to expect when the work is done. Some reasons why the painting can become matte:
- Oil colors, when applied on a porous surface or primer, become dull, dim and loose the luster. It happens because the oil from the paints is being sucked by the underlying surface This process is most noticeable in dark colors.
- If the previous layer of the paint didn't dry completely and you apply the next one – painting may also become dull.
Also the retouching varnish is used to enhance the adhesion of paint layers, which is very useful if your painting consists of many layers and a lot of time passed between sessions (when next layer is applied on a dry layer).
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| Professional Aerosol Varnish by Winsor & Newton |
2) Medium varnishes. Before using a varnish as a medium – carefully study the label or information on the website of the manufacturer, because not all of the varnishes can be used as a medium. For example, Winsor & Newton website says that “Dammar Varnish: the oldest liquid varnish, this gives a very high gloss. Winsor & Newton is the traditional 5lb cut if you want to use it for mediums (which we do not recommend but millions use it)»
3) Final varnishes create the protective film on the painting. Apply them only when the painting is completely dry, usually it takes more than 6 months.
Using a varnish as a medium (in a mixture with diluent/oil or pure) has several advantages:
1) Almost no dullness. Varnish doesn’t give the canvas (primer) soak the significant amount of oil from the paints.
2) The oil-lacquer paints have a good ability to stick to the surface on which they are applied, and stick to each other, because the essential oils contained in varnish are capable of dissolving (to a small extent) the underlying resin layer.
3) The layer of the paint becomes stronger. While oil dries from the top, creating a solid film that slows the drying in the deep layer, the resins dry from the bottom and, simultaneously, in the entire thickness of the layer. In the same period of time, oil-lacquer paint dries faster and more completely than oil, also all the paints dry almost simultaneously, as each of them contains a reduced amount of oil.
4) Resins are, in most cases, more transparent and glossy than oils. That is why oil-lacquer paints have greater richness and beauty of color than ordinary oil paints. However, most of the contemporary artists don’t like the excessive gloss of paint.
5) Oil-lacquer paints doesn’t blacken over time, because they are little permeable to water vapor and gases. The dampness is also less destructive to them.
Anyway, there are also some downsides of using the varnish as a medium:
- In addition to excessive gloss that most of the contemporary artists don’t like, there is another quality – varnish dries too fast on the palette and painting during the session. However, you can always choose a satin varnish and not use it as a pure medium, but in a mixture with oil and diluent.
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| Different versions of the same varnish - Glossy (consists of dammar resin and turpentine), Matt (dammar resin, turpentine and matting additives) |
There are two types of varnishes depending on their origin:
1) Traditional
2) Synthetic
1) The most popular traditional varnishes are Dammar/Damar, Copal, Amber, Mastic. There are 2 types of them – hard and soft.
Here is a perfect article about the differences between hard and soft varnishes, traditional versus synthetic and a lot of useful professional tips - http://willkempartschool.com/how-to-varnish-an-oil-painting/
Briefly, Hard Varnishes (Copal and Amber) were used by Old Masters, they are golden and give a rich gloss. However, they are hard to remove and they can crack and yellow over time. Moreover, they must be dissolved in hot oil (not in Mineral Spirits or Turpentine, as others) and they are rare in today’s world.
Amber Varnish by Alchemist Mediums. A specially formulated, high concentration of dissolved amber resin in linseed oil for use as a general painting medium. As it's written on the manufacturer's website - Alchemist Amber Varnish contains no driers, is solvent free and is all natural. Price: €85.00 for 60 ml
Soft Varnishes (Dammar/Damar and Mastic) - dissolve in solvents such as Turpentine and Mineral spirits, so you can remove them from an oil painting surface without greatly affecting the paint layers below. As a naturals resins, they have a tendency to yellow and crack.
2) Synthetic varnishes (MSA, Gamvar, Alkyd Synthetic Resins) Have a non yellowing and more flexible, than traditional varnishes, coat. In addition, they are available in liquid or aerosol form, can be matte, satin or gloss.
Conclusion:
Varnishes can be very useful, if you know how to use them right. Try them in a mixture with oil and diluent to give a layer more transparency and a painting extra gloss and shine. Usually, artists use such mixture on final layers.
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| Gamblin Oil Mediums Set |
As a medium to thin paints you can use:
- pure turpentine/white spirit (or any other diluent)
- pure oil
- pure varnish
- mixture of oil and diluent
- mixture of oil, varnish and diluent
Hopefully, this articles made the complicated world of varnishes and mediums clearer to you!
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| Mediums for oil painting by Gamblin |
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