Last month’s blog looked at colour theory and mixing primary colours in paint, key principles that I learned at art college. This month’s blog discusses another important concept in creating visually realistic paintings - that of tonal theory. By following a simple set of tonal parameters from light to dark, one can create a painting from direct observation that will look lifelike (or ‘photographic’, if you will.)

Let’s imagine that we’re creating a tonal study from life. Figure 1 depicts our subject, a naturally coloured scene with brightness and shadows. We don’t need to be concerned about colour here though, only shades of dark to light. Black and white are the parameters that we use. The lightest tone on a canvas or sheet of paper, for instance, is the white surface and we also use a white paint e.g. titanium acrylic. The darkest tone is the darkest pigment that can be applied e.g. mars black acrylic paint, black conte chalk etc. We then work out through observation what the lightest elements in the subject are; in this instance the sunlit reflection on the wall and church tower, and then the darkest areas such as the window holes and other architectural features. These correspond with our painting materials parameters of white and black to create a framework for deciphering all intermediate shades.

Figure 2 depicts the subject in just two tones of black and white only, without the intermediate shades of grey. At art college we started with this kind of approach (which proved tricky because the brain naturally wanted to see details) but it helped us in decision making and appreciate the concept of tonal relationships. Though technically tonally correct, figure 2 eradicates a lot of the information in the scene. The next stage, then, is to create a greyscale, starting with a mid-grey tone.

Figure 3 shows a painting that I made of the scene using approximately five tonal values from light to dark: white, black, mid-grey and two shades in between. I started as usual by establishing the lightest areas with white paint, and the dark elements in black. I then interpreted the mid-grey tone in the scene to be a large area that contained both the sky, shadowed walls and parts of the foreground. By comparing local shades in the composition I was able to interpret and select tonal choices for completing the painting. 

Working with tone from direct observation is a challenge because colour is always present in the mix, which changes the perception of tonal relationships. Two colours such as a red and green, for instance, can have the same tonal value but very different chromatic qualities. Place these two colours side by side and they appear to shimmer. Remove the colour saturation on a computer screen and the colours disappear to form the same shade of grey as seen in Figure 4. Optical illusions are designed to exploit these qualities and fool the brain’s interpretation of tone and colour in novel and surprising ways.

Other practical challenges face the artist when working with chromatic and tonal relationships. The limitations of paint pigments and other mediums often produce compromises when working with colour and light in a scene. Electric LED lighting, for example, produces both pure colour and light brightness but it’s difficult to recreate both in a painting without one or the other being compromised in some way. Ultimately it is formal problems such as these that have always challenged and motivated and inspired artists over the centuries to take image construction forwards in new and exciting ways.