Since the days of Ancient Greece, artists have used a concept of a triangle to group the composition of their paintings. The technique is rarely noticeable in the finished piece. However, the subconscious effect often lies at the root of a “good” painting.
The triangle is always an isosceles triangle with the long side on a horizontal plane. The two sides of the triangle are always equal in length. The triangle can either point up or down. The triangle can also be sub divided into more triangles of significance to the study of proportion. The Renaissance painters were also convinced that dividing a canvas into three sections helped improve proportion, and so the horizontal base is usually two thirds down the painting.
In the Greek practice of triangular composition, the proportions of the triangle were precise. The length of each side was equivalent to the width of the base times “phi.” The Greek letter phi corresponds to the number 1.618033988749895. Later, during the Renaissance, the mathematician Fibonacci discovered a series of number called the Fibonacci series. This series interested artists greatly as it was found to represent the proportions found in nature. The longer a Fibonacci series progresses the closer it gets to phi. Italian Renaissance painters used the Fibonacci proportions extensively. This was called the “Golden Ratio” and the triangle behind artistic composition was called the “Golden Triangle.”
The triangular composition has three purposes. It balances the features of a painting. It does not have to be central, but most cases in successful paintings are. The effect of this is to wean the viewer from a natural tendency to focus on the top left hand corner of any square. This is because in Western culture we are accustomed to reading text from left to right and from top to bottom. The triangular motive draws attention to the lower centre of the painting with a large subliminal horizontal stripe. It then leads the eye up to the point of the triangle, which will be the feature of the painting. The final benefit of the triangle is that it lays a guideline for perspective where horizontal lines slant towards a diminishing point to give the impression of depth.
Look at some examples of famous paintings and try to detect the golden triangle. Leonardo de Vinci’s Mona Lisa fits inside an invisible triangle. The triangle formed around Jesus at the centre of Michelangelo’s Last Supper is very clearly marked by the outstretched arms of Jesus and then is contrasted by an inverted triangle created by the positions of the two disciples wither side of him. Caravaggio’s Supper at Emmaus is illuminated by the knowledge that the artist made a conscious effort to create a triangle. The outstretched arms of the two disciples on either side of Jesus beckons the viewer in to the central figure and the triangular form of Christ extends out to the table at which he is seated.