All you need to know about varnishing paintings
Over the years dirt and dust will stick to the varnish rather than the painting and when the time is right, the varnish itself can be removed and the painting re-varnished to look as good as new.
Fixing dull paintings
If your painting is dull, it is easy to confuse the need for varnishing with the dullness created from colour that has sunk into the surface. If the colour has sunk then varnishing should be avoided, and the thing to do is ‘oil out’ those sunken areas using Artists’ Painting Medium (see our Tip & Technique on the ‘Oiling out Technique’).
Sometimes artists varnish their work to help stabilise surfaces with added texture or damaged layers, however, while varnish will certainly help, once the varnish is on it cannot be removed without damaging the work. If you have pictures like this, we recommend you keep the varnished work behind glass and think about how to improve your technique for the future.
What types of finished surfaces can be varnished?
Varnishes work well with oil and acrylic because the paint films are relatively thick and separate from the surface.
Varnishes do not work well with Gouache, water colour and drawings because the varnish will be deeply absorbed by the paint and/or paper, becoming an integral part of the picture and could cause discolouration. In addition, varnishes on works created using Gouache, water colour and drawing cannot be removed.
Generally, artists choose varnishes for the sheen they provide and also if they have been used by their favourite painters. Here is a brief overview of the different kinds of varnishes:
• Dammar remains one of the most popular varnishes even though newer varnishes have been introduced since its development.
• Gloss varnishes are chosen because they give the brightest, deepest colours but works with gloss varnish have a lot of reflection.
• Matt varnishes avoid reflections but the colours appear duller.
• All Winsor & Newton varnishes can be used on oil, alkyd, Artisan or acrylic paintings, however, all are designed with specific types of colour in mind.
The Winsor & Newton varnishes
For Oil Colour
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). As a strong varnish, we recommend using Distilled Turpentine (our strongest solvent) when it needs to be removed.
Professional Gloss Varnish: The most popular varnish, it gives a very high gloss finish. Stronger solvents will be needed to remove it as time goes by.
Professional Matt Varnish: One of the most modern varnishes, it is readily removable and gives a medium matt sheen. Professional Matt and Gloss varnishes can be intermixed for varying sheens in between. We suggest about 50:50 to achieve a Satin finish.
Professional Satin Varnish: A superior quality UV resistant satin varnish, removable with Artists’ White Spirit or Distilled Turpentine.
Re-touching Varnish: A UV resistant gloss varnish which gives temporary protection to recently completed oil paintings. It is quick drying and should be used in thin layers.
For Water Mixable Oils
Artisan Gloss, Matt or Satin Varnishes: These varnishes are formulated avoiding conventional solvents, ideal for communal studios or those needing to avoid hazardous solvents. These varnishes can be used on conventional as well as Artisan oil paintings.
Aerosol Varnishes: Aerosol varnishes are really useful for paintings with rough brushwork as a thinner layer can be applied. They are also preferred if you find applying with a brush more difficult.
Artists' Acrylic Gloss, Matt or Satin Varnishes: These varnishes are uniquely formulated to be removable and contain UV resistance with the Satin Gloss being mid-sheen in relation to the Matt and Gloss varnishes. The Galeria acrylic range also has its own range of gloss, matt and satin varnishes.
Top ten tips when applying varnish
1. Wait until your painting is completely dry.
2. Choose a dust free area to work in, keeping windows and doors closed.
3. Use a flat wide, soft, tightly packed varnishing bush such as the Winsor & Newton Monarch glazing and varnishing brush, keep it clean and use it only for varnishing.
4. Keep the work to be varnished flat on a table or work surface – avoid working vertically.
5. Stir the varnish well and pour it into a clean flat saucer or tin and load your brush. Wipe it on the side of the saucer so it is not dripping.
6. Apply the varnish in 1 to 3 thin coats rather than one thick coat.
7. Use long even strokes from top to bottom while moving from one side to the other, and remove any bubbles.
8. Once you leave an area, avoid going back over areas that you have done. For those areas that you have missed, simply allow to dry completely and re-varnish.
9. After you have finished, shield from dust with a protective plastic film (known as a ‘tent’).
10. Leave to dry for 24 hours and if a second coat is required, apply at right angles to the first.
Handling and hanging
It is best to avoid leaning varnished paintings together as they may stick.
If you use bubble wrap around your varnished painting or pick it up with your fingers touching the varnish, you may get impressions showing in the varnish. Avoid hanging pictures in bathrooms or kitchens, above radiators or open fires as they will certainly get dirty very quickly.