Our challenge is to represent our 3D world on 2D paper, and we do this by varying the light and the dark of our paints to try and mimic the light and shadows of our world.
But watercolour is a transparent medium and we generally do not have recourse to white paint, so how can we develop a wide range of tones in our work?
Swatching out tones
To lighten your watercolour, rather than adding white paint, you simply add more water and to deepen the tone you add more paint. It immediately becomes obvious that some colours such as yellow, are intrinsically light and cannot develop a wide range of tones… more of this later.
It is an incredibly beneficial exercise to swatch out a colour from full strength to palest tint in as even steps as possible. It teaches you all about controlling the water in your paint mix. There are two approaches. The first is to gradually add more and more water (see the turquoise strip below). The second is mix a large well of colour and use this in layers. It is applied to the 8 squares, which are then dried, then to seven squares missing the lightest, then six, five, four etc. Because of watercolour’s transparency the layers gradually add up and deepen in tone (see the purple example here).
In theory layering or glazing as it is called, should give you fine control over the tone of your colour. However this is a long winded process, with a lot of drying in between. In practise most people paint quite directly and then use glazing to fine tune the outcome.
Spheres and shadows
A sphere can be painted by first painting a circle and using clean water to blend the paint. A thirsty brush can lift colour from the highlight area. Additional paint can be charged in (tapped in from your brush), to the wet shadow area furthest from the light source. But what do you do if the colour you have chosen is not intrinsically dark enough to show the shadow?
You can see the parts of the light and dark labelled here. It is interesting to note that often in a dark side of an object there is a core shadow ie the darkest dark, but there is also a lighter area of reflected light. This comes from light bouncing off the surface.
There are two approaches to darkening your mix beyond its naturally range. The first is to add a complimentary colour which will darken your mix. So add green to red, purple to yellow or orange to blue. The downside is that this greys and mute the colour, but it is more interesting that adding in black or Payne’s Grey. The second possibility is to add an analogous colour. By this I mean, one which sits close on the colour wheel but which is darker in tone than the colour you are using. On this red ball, I chose a darker blue-red to use as the shadow colour to create the form. This kept the object vibrant, so this technique is perfect for flower painting where you want to keep exciting clear colours. If you wish to avoid greying yellow, do not use purple for its shadow, rather select a deeper orangey-yellow or even yellow ochre. For red, select a bluey-red and for blue, select a darker blue. You can clearly see the difference in the two approaches below.
The shadow on the object is the form shadow, but the shadow it makes is the cast shadow. Unless seen in bright light, the cast shadow will have indistinct edges and get lighter the further away from the object it is. Just as there is reflected light on the object, there may be reflected colour in the shadow – see the touch of red in the sphere example.
The case shadow will be a deeper shade of the colour of the surface, so all shadows are not grey! On a blue surface, the shadow will be deeper blue. The warmth of the shadow depends on the warmth of the light. In cool winter light, shadows are often warm – think of purple shadows on snow. In warm summer light, shadows are often cool – think of blue shadows in the Mediterranean. The area nearest the object is the darkest and this is sometimes called the area of occlusion.
If you would like to see all this in action, please head to YouTube: https://youtu.be/EjoNwt17sGI