How to use geometry to paint better pictures

By Artists & Illustrators | Mon 29th Jun 2020

Rob Dudley shows how identifying and adapting the underlying geometry of a scene can lead to better paintings


When looking at a good painting, one might be struck by the colour, tone, texture or simply the subject matter. But it’s often a combination of the unseen or hidden elements that underpin a strong composition that can really make or break a painting.

You may have heard of the ‘rule of thirds’ which is a useful device when designing and composing a painting or drawing. It involves dividing the picture plane into thirds, both vertically and horizontally. Strategically placing key elements along these lines or at the points where they intersect is likely to result in a visually pleasing arrangement.

As a result, a hidden structure underpins the subsequent picture’s design. Indeed, my sketchbook is littered with little drawings within which I’m exploring possible compositions based on the ‘rule of thirds’.

However, I also find it useful to break a design down into other geometric elements when planning my paintings. These include horizontal, vertical and diagonal lines, as well as triangles, or what I like to call ‘signposts’.

Each painting becomes a combination and a balance of these geometric lines and shapes, and, although they are often lost to the viewer, their presence is essential in the production of good paintings. Their contribution is as important as those of tone, colour or texture, and should be considered accordingly.



Horizontal elements within a painting will appear to move the eye across the painting, often from one side to the other. Within the landscape these horizontal elements are likely be found in hedgerows, walls, distant skylines or even clouds. In seascapes, the horizon or waves rolling onto the shore often provide the horizontal element.

Horizontal lines are said to bring a calm, stable feeling to a painting. In the painting above, note how the horizontal skyline of the trees and the riverbank moves the eye from one side of the painting to the other. Even when the bank stops, the horizontal movement is strong enough to continue to the other side of the river. The calmness of the scene is underlined by the use of these horizontal elements.



The inclusion of vertical elements often brings a dynamic, thrusting movement to a painting – and the stronger the element, the more dynamic the movement. Within the landscape, trees are the most obvious vertical element. However, a line of fence posts, a church tower, or even a well-placed telegraph pole will offer a similar upward flow.

The strong vertical movement of the shadowed trees carries the viewers’ attention up through this painting. Note also how tone comes into play: the lighter, thinner trees still carrying an upwards movement, yet they do not carry the same weight of thrust as the darker ones do.



A strong diagonal can lead the eye into the three-dimensional picture space, so they are particularly useful for creating a sense of depth and distance within a painting. In a landscape these diagonal elements might be seen as a river or stream, the patterns of a freshly ploughed field, or even a slanting shadow falling across an open moorland. Curving lines play a similar role, but offer a softer, less dynamic movement compared to that of a straight diagonal.

The painting above, Barns in the Lane, contains several strong diagonals leading the viewer towards the sunlit end of the shadowed lane. The lane itself is probably the most dominant, but the hedge, the trees on the right, and the barns contain strong thrusting diagonals.



Signposts, which are often suggestive of triangles, help to point the viewer to elements within the painting that the artist wishes to focus on. These might simply be a directional brush mark or the grouping of trees or boats that serve to nudge the viewer’s eye in the right direction.

In this watercolour of Topsham at low tide, note how the clouds to the right have been grouped together to lead the viewer’s eye towards the primary focal point. The triangular brush marks within the mud and the sparkling foreground are all shaped like signposts as well to direct attention towards the key focal point where the light on the water is brightest.

Combining lines and signs


A good friend of mine took a great photo of the River Yealm at low tide. It had everything in it that I enjoy painting: boats, water, trees, and – my favourite – soft light bouncing off wet mud. Happily, she allowed me to use it for reference.

Newton Ferrers is a location that I know well and have painted it many times. Working from the photograph and from other drawings I sketched out some thumbnail designs, exploring the underlying geometry of the painting. My aim was to work out how I could combine the geometric elements to produce a stronger, more interesting painting. The painting Low Tide at Newton Ferrers is the result of those explorations.

The strong diagonals of the foreground channels were useful as they led the viewer into the painting, the zig-zag movement carrying the viewer further into the picture towards the misty distance. To emphasise this movement, I strengthened both the tone and colour of the channels. But in order to prevent this movement from dominating the whole of the painting, I introduced some horizontals in the far distance. They would act as a contrast to the dynamic foreground, bringing a sense of calm, more akin to the mood I was trying to capture.

The church tower on the left, the trees on either bank and the masts on the boats bring a balance of verticals to the design. If these vertical elements were absent, I would have had no hesitation in ‘inventing’ a few. Indeed, when planning any painting I am always conscious of the possibility of adding additional elements should the design require them.

The mid-ground mud on the right added little to the overall dynamic of the panting so I decided to add another channel, triangular in shape, which acted as a ‘signpost’ pointing the viewer’s eye back into the painting and preventing attention wandering elsewhere. Once these elements were settled upon in my sketchbook and I had also made decisions over tone, colour and format, I was free to begin my painting, safe in the knowledge it was based on a sound structure.

Good paintings don’t just happen, they have to be worked at. Over the years, I have found breaking paintings down and considering their underlying geometry at the planning stage has always resulted in stronger, better and more satisfying paintings.

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