Duration Two hours
Materials Plumb line or length of string approx 1.5 metres, metre rule or straight stick, 15cm metal rule, charcoal or chalk, small brush, black oil paint, solvent
What will I learn?
While measurements can help to plot the position of your objects, an understanding of the picture plane can help you create the illusion of space. In painting, the picture plane refers to the flat surface of the canvas on to which the paint is applied. It is a notional plane that generally refers to the front of the surface on which you're painting. The distance between you and this notional plane determines the scale of the work. In this exercise, you'll learn to construct the illusion of depth and three dimensionality by penetrating the picture plane.
Method
1. Create a tabletop still life, placing the objects towards the back of the table. Place the table edge parallel to your painting support. In order to have some mobility, it's best to work standing up.
2. Mark the position of your feet on the floor so you keep a consistent viewpoint. Hold your plumb line at arm's length and wait for it to stabilise. With one eye closed (always close the same eye from here on!) position the line so that it bisects the centre of the still life.
3. By trial and error (or with the help of a friend) line up the edge of your metre rule with the vertical edge of the plumb line, on the table top. Having done this, draw a vertical line in chalk or charcoal along this rule. The line will bisect your still life and represents a projection of your line of sight on the tabletop.
4. At a point somewhere along the line of sight, rule a second, perpendicular line across it on the table. You can use this as the baseline of your picture plane or you can place the baseline nearer or farther from here if you think it will make a stronger composition.
5. Now paint your vertical line of sight on to your canvas. Remember that the bottom edge of your canvas should coincide with the picture plane baseline (ie the perpendicular line you've just drawn).
6. Decide where you want the upper cropping point of your composition to be. Select a unit of measurement, such as the height or width of one of the objects in the still life (for example, if you have a cup in the still life, use the height of the cup as your unit). If there isn't an obvious unit in your still life, you can make one by marking off a distance on the line of sight you drew on the table. Now measure how many repetitions of this unit will take you to the top of your composition. To do this, stand in the position you marked on the floor earlier, hold your ruler at arm's length and, closing one eye, measure your unit of measurement (for example, the height of your cup). Then count how many of these units take you from the baseline to the top of your composition.
7. Now divide the height of your canvas into the same number of divisions, making small marks along the side of your canvas.
9. With reference to the baseline and to your line of sight, start to plot the positions of objects in your still life. To do this, use your ruler as before to measure the distances you see. For example, how many cup-heights away from the top of the composition is your cup?
10. Hold out your arm and point along the line of sight on your table, balancing the short ruler across your index finger to form a horizontal - use this to compare angles between objects. Some points you assumed were aligned might not be, while others might be surprisingly horizontal.
11. Continue plotting key points until the act of measuring and drawing with the brush becomes intuitive. Don't worry if you make mistakes. You can always make alterations by removing colour with solvent.
What do the results show?
This workshop will strengthen your perceptual skills and make you think about angles and space in your compositions. Although the rigour of working with the picture plane is not for everyone, it is a valuable experience that challenges assumptions about what we see and how we translate that into marks.