Myth-busting watercolour mediums: common misconceptions debunked

oils mediums varnishes

Are you feeling overwhelmed about the dos and don’ts of how to apply watercolour mediums? Below we’ve collated the most widely misunderstood myths and put them to the test with answers from expert artists. 


Myth: Watercolours aren’t opaque. 

Debunked: False. Much like any other paint, watercolours come in both opaque and transparent colour.  

A great benefit of watercolours’ fast drying speeds is that they can also be layered and built up to increase opacity. If this still isn’t enough, watercolours can be mixed with their more opaque cousin, gouache, for stronger colours. 


Myth: I can’t use watercolours on canvas. 

Debunked: On gessoed canvas this is a no-no, as watercolour will have nothing to absorb into and will quickly crack without an acrylic medium to help it stick. However, on any non-primed fabric, watercolour will absorb nicely.  

In fact, water-based paints have been used for centuries on materials such as linen and silk. You can also ‘stretch’ paper to prevent it from buckling as you work bigger, largely eliminating the need for canvas all together. 


Myth: I can’t use gesso for watercolour. 

Debunked: Though watercolours need an absorbent surface to soak into, and gesso is non-absorbent, watercolours can be mixed with acrylic mediums to get around this. Watercolours have also long been used to tint gessoes for colour grounds too! 


Myth: Watercolour lifts on its own, so an added lifting medium is pointless. 

Debunked: In heavy washes and on more absorbent grounds, watercolours will soak more and be tougher to lift with water. Lifting Preparation ensures that your colours are always lifetable no matter the surface that they are painted on. 


Myth: Only certain colours have granulation. 

Debunked: While this is true in theory, with Winsor and Newton’s Granulation Medium all colours can be made to granulate, with those already possessing this quality being pushed even further. Try more textured papers and even adding salt to your mixture to achieve more extreme results. 


Myth: Watercolours are flat. 

Debunked: Not true. Watercolours can be mixed with Winsor & Newton’s Texture medium or Aquapasto to lend structure to your paintings. Chalk powder or ‘whiting’ can also be added to increase texture and opacity. Essentially a thickened Gum Arabic, the Aquapasto can be applied over damp paper as a glaze which can be painted into, allowing stokes and marks to show their texture more. It’s a great way to glaze over under washes which can later be revealed via scraping through with something like a brush handle.  


Myth: Watercolours always bleed under taped edges. 

Debunked: This can be avoided. Using mediums like Gum Arabic and Ox Gall will help increase surface tension in your paintings, meaning there’s less chance for bleeding.  

Another option is to try Winsor & Newton’s Masking Fluid – sticks and other implements can be used to draw or print with the masking fluid, which can be an interesting process that both prevents bleeds and gives you the freedom to mask off areas in any shape you like. Avoid using Masking Fluid with brushes as it can spoil them.  


Myth: I can’t varnish watercolours. 

Debunked: Varnishing watercolours in a conventional sense is tricky, as a water-based varnish is likely to lift your colours and alter your painting. An alternative is to use Winsor & Newton Fixative, an archival quality spray fixative made for dry media that also works perfectly well protecting watercolours. 


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