To varnish.. or not to varnish… that is indeed the question!

The purpose of varnish is to protect a painting from dirt and dust and even out the painting's final appearance, making it all equally either glossy or matt. Over the years, dirt and dust will stick to the varnish, rather than the painting which is the good news, however, this will mean at some point the varnish itself will need to be removed and the painting re-varnished to make it look as good as new. Sounds simple, but it’s not!

I have been unsure of varnishing my oil paintings for many years because traditional solvent (with strong fumes) and Shellac/resin based varnishes can cause yellowing and cracking over time and they are not easy to remove.

I recall a specialist painting restorer saying many years ago about how a mixture of cigar smoke stains and the actual resin based varnish damaged the painted murals in the music room of the Royal Pavilion in Brighton. She said that the experts had decided to not revarnish it, as they found it easier to restore the paint without it. There were also some impressionists that preferred their paintings to remain unvarnished, with a more natural appearance.

The varnish on Picasso’s Guernica painting however protected it from the vandal’s red spray paint, as it was easily removed without harming the picture.

Little was talked about the varnishing of paintings at art college or in painting classes, so with the fumes and the cracking and the potential damage it really does leave one with the conundrum; what is best - or least harmful.

Having raised this question in my mind, I undertook some personal investigation and found that varnish is generally recommended to protect the oil colours from dust damage, UV damage and general damage, as well helping to revive colours that have sunk in/gone dull (a tendency with some colours and on more porous grounds), to retain their vibrancy. A lot of more traditional artists like the gloss finish, as it adds depth to their paintings and it makes them look more finished, although this can create glare in certain lighting conditions. If a buyer is paying for an expensive oil painting, they often expect a varnish on it, to protect it. Modern abstract painters often like the matt finish for the flat appearance.

With traditional varnishes, it is recommended that oil paintings be left for at least 6 months before applying them on top, although Dammar, one of the oldest and most popular liquid varnish, can be used with the paint in layers as glazes.

There is a lot more choice on the market nowadays with the research and scientific developments of synthetic varnishes. Gamblin in the USA developed their Gamvar varnish with the National Gallery’s picture restorer, and other similar ones are on the market. This varnish is said to not yellow and crack, as well as being easily reversible; which makes life easier for picture restorers and the fumes are much lower than the traditional Shellac/resin/solvent types.

Picture restorers usually recommend reversible varnishes that can easily be taken off, without damaging the paintings. Finishes such as Gloss, Satin or Matt are available too.

An advantage of some of the synthetic varnishes is that they do not require a great length of time for the paint to dry and can allow the paint to breathe.

Synthetic retouching varnishes are not the top coat but can be used to help revive colours that have sunk in and can be painted over. It is seen as a temporary finish. Top finish coats  of another varnish would be required. Some experts recommend that if retouching varnish is used that the gloss version is preferred with a top coat of a finish that an artist is wanting added on top.

He is a link to an article that is useful in explaining further.

Here is what Windsor and Newton have to say.

They are also many YouTube videos I found on-line on the methods of applying varnishes.

Recently, there has also been recommendations for varnishing acrylic paintings and there are safe products available for these. I would recommend anyone contemplating this to carry out their own research before they begin.

To conclude, a note of caution, if you decided to varnish you must always follow the manufacturer’s recommendations before applying, for your own health and safety and the health of your painting.