Watercolour: 3 Ways to Varnish
Imagine if a watercolour could be varnished like an acrylic or oil painting and framed without a mat or glass. The appeal is great — no more glare, no more cracked or broken glass, lighter to transport and easier to store. The good news: there are now a number of new products to help you. The bad news: this is an experimental, and somewhat controversial, process.
In fact, there are some in the watercolour field who disagree aesthetically with varnishing, claiming the results can no longer be called a watercolour. We explain it would simply be called an ‘encapsulated watercolour.’ Some artists have found that their encapsulated watercolours sell well. For your reference, here are some of the suggestions we have heard about. You can conduct your own experiments and decide how you want your watercolours presented.
Remember to photograph all artwork before varnishing or it may show a reflective sheen.
Here are three methods for coating a watercolour
Process I: Wax the Surface!
Here is a method that is quick and easy. The waxed watercolour is mount to a birch board. The process is well-presented in this popular video.
Process II: Isolation Coat and Acrylic Varnish
1. Watercolour paper that is to be varnished needs a firm support beneath it.
Then a watercolour painting can sit in a frame like an oil painting (no glass or mats are needed). There are several suitable choices:
- Paint watercolour on rigid support. There are a number of modern acrylic grounds that can be applied to canvas or wood panels so the surfaces will more readily accept and hold watercolours. Examples include Golden Qor Grounds, Daniel Smith Grounds or Schmincke Grounds.
- Purchase watercolour paper mounted on board like the Canson Plein Art Art Panels.
- Watercolour paper can be directly mounted onto birch panels using Golden Soft Gel as the glue. Gels are ideal adhesives. They are non-yellowing, non-cracking and durable.
2. Use an Isolation Coat and MSA Varnish
Apply varnish and isolation coats with an airbrush. Any airbrush will work, using a wide spray pattern. Aztec Single Action Airbrush kits come with compressed air in cans and are easy for novices to use. The air compressor must be adjusted to 35 to 45 psi. Note: Always wear a chemical spray mask while varnishing, and mount an exhaust fan in a window.Keep the airbrush about 6-8″ away from the original. Let each coat dry thoroughly at least 1/2 hour.
Apply an isolation coat. Its purpose is to seal the watercolour so that subsequent varnishing does not disturb your painting. It is wise to take a careful approach at this stage so that nothing is smudged or marked. Spray two coats of Golden GAC 500 diluted with Golden Airbrush Medium. Golden also makes Isolation Coat. This will protect the original watercolour. It acts like an acrylic sealer that keeps the varnish from touching the original, and allows the varnish to be removed later on if needed.
Apply the varnish. Golden Polymer Varnish UVLS is a concentrated, water-based varnish (available in gloss, satin, or matte). It should be mixed 50/50 with the Golden Airbrush Extender to run more smoothly through the airbrush. UVLS stands for ‘ultraviolet light stabilizer,’ which will help protect your watercolour from fading. Ideally, you should use 6 to 8 coats of the final varnish. Let each coat dry thoroughly. Because the polymer varnish requires extra care and may permanently bond with the GAC 500 (which is also water based), Golden MSA (Mineral Solvent Acrylic) Varnish is preferred by some artists. It is easier to remove from the acrylic isolation coat using artist-quality painting solvent.
Process III: If you don’t have an airbrush
If you do not have an airbrush, Golden MSA Varnish can be purchased in aerosol format. It is a solvent formula an must be used in a well-ventilated area. Simply apply 8 to 10 coats to your rigidly mounted watercolour and you will be able to frame it without using glass. Another popular use for the versatile MSA Spray Varnish Varnish is protecting prints, laser prints, inkjet copies and other reproductions.
WARNING: Don’t rush the coats of varnish. The mounted paper can become too damp and it will bubble or warp. Let each coat dry for at least a 1/2 hour. Humidity is a factor. Touch the paper, and if it is cold or cool let it continue to dry. (Another note of caution for painters who scrub out areas and damage the paper: this can really show up when you varnish, especially in dark areas of the painting.)
Allow the varnish to dry (cure) overnight before framing.
More Tips for Watercolour
- Watercolour Gouache Comparison
- Watercolour An Introduction
- Watercolour Masking Fluid
- Watercolour Pans vs Tubes
- Watercolour 12 School Projects
Kim Fjordbotten: As owner of The Paint Spot, Kim Fjordbotten is passionate about helping artists use materials and make art. She is available as a speaker and educator for teachers and art associations. The Paint Spot offers exhibitions, classes, and beautiful art materials to inspire your creativity.
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