Friday, October 1, 2010

How to Varnish a Painting

For those who are new to painting and want to know how to varnish a painting, whether it be acrylic or oil, you can use this process.

So what varnish to use?
I am an Acrylic painter so I originally started using a varnish suitable for acrylics. Jo Sonja's and Atelier brand Matte or Gloss Varnish. Acrylic varnishes are water-based polyurethane which creates a plastic like film over your painting which seals it. However I decided to experiment with a few different type of varnishes including Cabots Crystal Clear. You can buy this from the hardware store and is water clean up and made from polyurethane too however I felt this type of varnish was better. I found the Artist's Acrylic varnishes to remain tacky and collect dust, whereas Crystal Clear dried 'dry' with no tackiness. Than I discovered varnish which oil painters use, it is solvent based therefore turps clean up. That is the only downside to using a solvent based varnish, however the result out ways the infrequent inconvenience. The advantage is, no tackiness and therefore easily wipe painting clear with slightly damp cloth. Downside, you must be sure your have completed your painting, as you can easily repaint over an area with acrylic paint as the solvent acts as a resist. With oil paint however I assume it would be ok.

What to choose: Gloss or Matte?
Well really the finish is your choice, there is no right or wrong. Depending on your painting will depend on what would be best. For example, a bold abstract piece might look better as a gloss, or a realist scene may be better as a matte. For me, I like to go in between and go for Satin (Semi-gloss). Just remember, if using a Gloss, be aware that photographing the finished piece after varnishing may reflect light. So photograph before and after.

How to apply varnish.
Applying varnish again is a personal choice. Ways you can include painting in the direction of the format e.g. Portrait or Landscape, or left/right or up/down. Or paint in the direction of the subject e.g. follow the curves of a portrait; down the nose, round the checks, across the forehead etc. Or the way I varnish is using cross-hatching or hatching technique. This ensures I seal every part of the canvas.

Step One: Step up what you need:
  • Varnish.
  • Ceramic container.
  • Newspaper/Drop Sheet.
  • Brush.
  • Gloves
  • Brush Cleaner
  • Wood Blocks or Painter's Triangles. This is rather then placing canvas directly on the newspaper as when the varnish dries, the paper sticks to the varnish and leaves unpleasant bits stuck to the canvas.
Painter's Pyramid is something I accidently found in the hardware store (Bunnings for $12.00). They are great for varnishing or just painting to get to those edges without painting the table.

Step Two: Paint the sides first
(except the very nearest side to you incase you touch when leaning over). This is so if blobs of varnish pools on the edge it gets wiped flat when you do the surface.

Step 3: Paint the surface using method of choice. I use hatching and cross-hatching stroke. Other suggestions: Left to right, top to bottom or directional.

  • Wether it is water based or solvent based, try not to keep painting over the same area as this folds in air and creates little bubbles.
  • When you feel the varnish is tacky or 'grabbing' move on, this indicates you have already painted there.
  • Make sure varnish is dry before storing.
  • Use gloves if using solvent based
  • Clean brush with brush cleaner or soap and water
  • Don't use your best brush but do use a suitable one. A synthetic long flat.
  • Use glass or ceramic containers so you don't have to throw away disposable plastic
  • NEVER pour turps down the sink. Pour excess into a jar for next time (yes you can reuse the turps until it is too dirty) or pour onto newspaper and discard

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