Why Do Paintings Need to be Varnished?
Varnishing has several purposes: most of all, protecting the painting and evening out the surface shine.
Specifically, the purpose of varnish is to:
- To protect the paint from atmospheric attack
- To even out the mixture of matte and gloss areas of your painting that have occurred due to different amounts and types of mediums being used in different areas around the work
- To deliberately raise or lower the level of gloss that the paint will have on the finished work
- Occasionally, for paintings that are destined for strongly lit areas, as a UltraViolet protection to reduce fading of the pigments in the artwork.
Tip for Fine Art Collectors
This is so important for investment art or prestige art pieces you are thinking of purchasing.
Make sure to ask the artist, gallery owner or dealer who is selling it to you, whether this painting has had varnish protection added to it, and what sort.
Preserving the Painting
The old masters often varnished their paintings and that is why we can still see some of them so clearly today. Over hundreds of years, the layer of varnish has absorbed the acid, grease, dust and grime in the air over the paintings, and the art museum staff have removed the layer of varnish to restore the painting to its former beauty. A new layer of varnish can be added to protect the painting for another hundred years (I am not sure the museums do this so much when the paintings are stored in such clean, climate controlled environments like art museums and galleries now!)
You can do the same for your paintings, to keep them safe for many years.
I always try to keep the materials I use on paintings as safe and long living as possible (in other words, “archival”). One reason for this is that I never want a client who has bought a painting, for example, to come back to me in ten years time and tell me that the painting they bought has cracked. If that disaster ever happened, the only solution to that would be to paint the artwork again from scratch, and even if it were possible to replicate it again exactly (which I couldn’t), I also have no desire to do that. Let alone having an unhappy client!
I want all my paintings to stay in one piece and last for many years for clients. For that reason I research carefully the chemicals in paints, mediums and varnishes, and make sure all the different layers and how they are applied will ensure the painting has longevity.
Here’s what I tell people in my art classes who ask me about which varnish to use
Here’s the Key
In order for varnish to be removable, it must be a different chemical composition to the paint underneath
In order for varnish to be removable, it must be a different chemical composition to the paint underneath it, that it is trying to protect. You want a separation between the paint and the varnish so that the varnish can be swabbed with a particular type of solvent that dissolves the varnish but not the paint. Then the varnish can be removed safely without disturbing your precious painting underneath.
Varnishing Acrylic Paintings
For acrylic paintings, I use a solvent varnish. Acrylic acts a lot like plastic when it is dry so that a solvent that dissolves the varnish will not dissolve the plastic of the paint underneath.
While your acrylic paint brushes can be cleaned up in water, the brush you use for applying your solvent varnish, must be washed up in turps, unfortunately.
My favourite varnish for both oils and acrylics is a nice rich clear, non-yellowing gloss varnish. I like the shiny look that gloss varnish gives to the paint, so that it looks like a rich, wet oil paint. The thing I also like about gloss varnish is that it gives a clear view through to the paint colours underneath. The satin and matte varnishes are often filled with little particles to take the gloss away, and can disrupt your clear view into the painting. For this reason they will often tell you that if you want a matte finish with several coats, you should do all the coats but the last one in gloss, and then just finish off with one matte coat.
For acrylic paints I am currently using Chroma brand Gloss Solvent Varnish.
Winsor & Newton has a range of varnishes for acrylic paintings which are a little more expensive. I love Winsor & Newton though: they have such good quality products, and the information they provide online is amazing.
I only do the final varnish after the acrylic paint has fully cured (usually one month). If it is important to do a quick temporary gloss coat sooner than that, I use the Atelier Interactive Gloss Varnish. This used to be called Gloss Medium and Varnish – they have since renamed it, just to confuse us. The bottle still clearly states that it can be painted over. This is a varnish that is safely “retouchable”, meaning that you can paint over the top of it without problems, since it is a medium similar to your acrylic paint.
Varnishing Oil Paintings
For oil paintings, in the old days Damar varnish was used (again, a different chemical structure to oil, and therefore removable) but I find Damar a bit too yellowing for my liking. I prefer to use a professional artists’ varnish for oils. This must not be used until the painting has dried and cured thoroughly, which means six months for a reasonably thin oil painting, twelve months for a thick impasto painting. If the varnish seals in the paint too soon before it has dried completely, you may be in for some wrinkling or cracking (i.e. disaster!).
If you want a nice glossy finish for an exhibition long before the six months is up, you can use a different type of temporary, or “retouchable” varnish that is able to be used for oils after only one month for a thin painting. This type of varnish should not be regarded as a final varnish. It is the same chemical composition as the oil paint and can be painted over later. It is not removable. You still need to to a final coat of protective varnish after the full drying time has elapsed.
For oil painting my favourite temporary (retouchable) varnish to use after one month of drying is Winsor & Newton Artists’ Retouching Varnish for Oil Colour.
For the final permanent varnish (after 6-12 months) I use Winsor & Newton Artists’ Gloss Varnish for Oil Colour.
Applying Varnish: Spray or Brush on?
I never ever spray varnish my paintings. If you really want to get some really toxic poisons into your system as fast as you possibly can, just spray varnish in the air at your paintings and accidentally breathe in some of the vapours. No thanks, not for me.
I always buy the varnish in a bottle, that I can pour on the painting then spread softly with a big flat bristle brush, then leave it to air in a room that has good airflow and no human beings hanging around in it.
If you are going to Learn to Paint, learn to look after the beautiful paintings you create!
Check out Part 2 for step by step instructions on how to varnish!
What experiences have you had with varnishing? Have you ever varnished your paintings before?
Why not check out our latest blog on the Two Great Acrylic Mediums that I love to use.