It is usual in watercolour to work on white – it lets the transparent colours sing, but there is no reason why you shouldn’t use a coloured paper. If that was good enough for Turner, who are we to argue?
Using a coloured or toned ground/paper can create colour harmony. It can establish the mood of the whole painting. It can simplify or cut down on the time taken to complete a piece too. Afterall if you plan to start the painting by doing a background wash, why not just use a piece of paper that colour?
Coloured watercolour papers are available (Bockingford do a range of cream, oatmeal, grey, blue and green) or you can use pastel papers. If you are using pastel paper you will find it is very light weight and will cockle. So you need to stretch it. On the whole, I think life is too short for stretching paper. The alternative is to apply a thin wash of acrylic to watercolour paper. The advantage is you get exactly the colour you want and it is permanent, though it will alter the way watercolours react with your surface. As always, approach it with a spirit of adventure and see what happens!
The colour you choose should refect the mood and atmosphere of what you are painting and should complement the colours you choose.
But what about lights and whites, I hear you cry? You may wish to use gouache, which is opaque to obtain tones lighter than the colour of your paper – if you have white gouache then you can tint it with watercolours to make whatever shade you fancy. Or you can choose to have the tone of the paper as your lightest shade. And what is gouache, I also hear you ask (I am hearing a lot of voices today!)?
Gouache is a more opaque form of watercolour. Gum arabic is used to bind the pigments but instead of the white of the paper providing the light for watercolours, gouache has white pigment such as chalk to enhance the opacity. Gouache forms a layer of paint on the paper surface and does not allow the paper to show through. If you think back to the old Ladybird books, the illustrations were often painted in gouache before acrylics gained wide popularity.
I did the cityscape above to demonstrate watercolour and gouache (with a spot of ink) on a grey ground. I hope you can see how even though I used quite bright colours in the buildings, the overall grey has produced a fairly subdued result. I am definitely a country person, so it’s how I feel about London – nice to visit, a bit grey even in the sunshine.
Do have a play with coloured papers and it may add a new dimension to your painting.