Depth Perception in Art

In this post, Harvey looks at the different tricks and techniques artists have employed throughout the ages in order to create a sense of depth in their works.

If you were to look at any painting of a landscape scene, you would probably take for granted the spatial depth that it conveys. However, those works began simply as a blank two-dimensional surface. Through the trickery of visual illusion, artists can create the impression of a three-dimensional image on a flat surface. Depth perception in the real world requires the use of both eyes, known as binocular cues; you may have closed one eye and attempted to touch the ends of two pencils together with varying success when you were a kid. However, the opposite is true for perceiving depth in pictures. You can gain a much more profound sense of depth when looking at a 2D picture with only one eye. Although modern artists have access to the tools and knowledge to create very convincing 3D works, art wasn’t always so representative of the real world.  

Shadows and hiding

Travelling back to Ancient Egypt, the figures and objects depicted in their art look notably two-dimensional, appearing to be lined up independently one after another. The proportion and sizing of the objects were also skewed, being based on their relative importance instead of their actual dimensions. However, if you look carefully, you will notice that even some of the oldest pieces of art utilised a depth-producing technique; overlap. Although fundamentally basic, using an object to obscure or overlap with part of another gives the impression that the object on top is closer to the observer. In this Walter Crane painting titled ‘Study of trees’, we assume that the trees which have been occluded are behind the trees in the foreground because they are partially obscured by them.

Walter Crane (1845 – 1915) ‘Study of Trees’ (1863), Source: the Whitworth, the University of Manchester.

For several centuries, overlap was the only technique used to create the impression of three dimensions. The understanding and knowledge behind more sophisticated techniques were actually developed through Ancient Roman and Greek mathematics, although it took several centuries for these ideas to resurface and be used in practice. It wasn’t until the Classical period that newer techniques began to be commonplace, where artists began to use shadows and shading gradients. The ancient Greeks were the first artists to create cast shadows, establishing the concept of the shadow’s position in relation to a light source. Plato, however, was a shadow critic; in his allegory of the cave, he criticised and mistrusted shadows, proposing that they masked reality’s true nature. Barbara Hepworth has very aptly used contours and shadow to give a greater suggestion of depth to parts of her sculpture ‘Coré’.

Barbara Hepworth – Coré (1969). Sculpture. Bronze. The Whitworth, The University of Manchester © Bowness.

Perspective is Born

The art produced during the middle ages and earlier was rich and inventive, but there was no attempt to create the three-dimensional works we are now accustomed to. This all changed due to one hugely influential man who provided the foundation of linear perspective during the Renaissance. Often thought of as the godfather of Italian architecture, Brunelleschi demonstrated the use of linear perspective with his landscape painting of the city of Florence. By having parallel lines converge into distant vanishing points as they recede away from the observer, Brunelleschi’s works were the first to simulate a realistic scene on a 2D platform. Linear perspective grew in popularity among artists as Italian realism became the newest style. This Edgar Wood painting of a street scene in North Africa uses linear perspective. The street disappears off into the distance, and the parallel sides begin to converge into a seemingly infinite point. 

Edgar Wood (1860 – 1935) ‘Street Scene in North Africa,’ (1914), Source: the Whitworth, the University of Manchester.

As artists began to demonstrate full command of linear perspective, its framework allowed for new techniques to emerge. One technique born during the Renaissance period was relative size, the process by which objects seem larger or smaller depending on their distance from us. Take a look at this landscape drawing by Paul Sandby. 

Paul Sandby (1725 – 1809), ‘Conway Castle, Caernarvonshire, Wales, from the South West,’ (1802), Source: the Whitworth, the University of Manchester.

Even though the horse looks roughly the same height as Conway Castle in the background, we interpret the castle as being further away – not that it was a castle made for ants! This is because we humans are particularly intuitive animals; using what is known as top-down processing (our knowledge and experiences of the world), we are able to interpret whether the difference in size is actually due to size or to distance. The mathematics of linear perspective also advanced ideas in how height could relate to depth. Relative height is less obvious and a little confusing, but can still provide us with critical three-dimensional information. When looking at a scene that is below our eye height, then the highest object will be the furthest away. Similarly, if we view a scene that is above our eye height, then the lowest object will be the furthest away. If those statements get scrambled up in your head (like they often do in mine!), then take a look at this Johann Jongkind watercolour titled ‘Dordrecht harbour’:

Johann Berthold Jongkind (1819-1891), ‘Dordrecht Harbour’, Source: the Whitworth, the University of Manchester.

Notice how Jongkind has created the illusion of depth by painting the more distant ships closer to the midpoint of the picture. Although a little tricky to make out, this Turner watercolour, ‘Coniston Fells’, also uses relative height to create a sense of depth. Unlike the Jongkind watercolour, these clouds are above eye height, meaning that clouds further down appear to be further away.

Joseph Mallord William Turner (1775-1851) ‘Coniston Fells, Lancashire (recto); Landscape with Waterfall (verso)’ (1801), Source: the Whitworth, the University of Manchester.

Atmospheric perspective

Atmospheric perspective (my personal favourite) is an interesting and very astute method to convey depth in a two-dimensional picture. Instead of using information based on shape or size, modulations in colour can be used to simulate how light is affected by the atmosphere over distances. We perceive the world around us through light particles entering our eyes, meaning the light from more distant objects has to travel further. The presence of the atmosphere combined with minuscule particles in the air generates a scattering of light. Think back to the days of secondary school physics and the electromagnetic spectrum! Short-wavelength light, the colour blue, scatters the most, whilst long-wavelength light, the colour red, scatters the least. This results in distant dark objects having a blueish hue, whilst distant bright objects appear more reddish.

Although the use of atmospheric perspective has been utilised well before, the term was coined by Leonardo da Vinci who noted in his Treatise on Painting that colours “become weaker in proportion to their distance from the person who is looking at them”. British landscape painter J.M.W. Turner was a true master of this technique. He whimsically referred to atmosphere perspective as ‘tinted steam’ and believed that its ambiguity was an artwork’s most attractive and engaging quality. Through his experiments with watercolours and oils, Turner began to produce a substantial presence of atmospheric perspective. In this piece titled ‘Lake Lucerne, Sunset’, note the saturation increases with the distance, as well as taking on a bluer hue as it recedes into the distance. By complementing this with some of the other techniques we mentioned, such as linear perspective and texture gradient, ‘Lake Lucerne, Sunset’ conveys a dramatic sense of depth:

Joseph Mallord William Turner (1775-1851),
Lake Lucerne, Sunset, (1845), Source: the Whitworth, the University of Manchester.

Defying the rules

It is clear that the techniques used for creating a sense of depth had been well established in the 19th century. However, by the end of the 1800s, the post-modernist movement began to take a critical perspective on why art should be seen to be a realistic representation of the world. Artists such as Paul Cezanne began to ignore the laws of classical perspective, depicting each object as independent from another. These new ideas of composition inspired avant-garde movements such as Cubism, where artwork often rebelled against realism. Nowadays, you can always look to the streets to find creative usage of depth. With all the depth cues of old at their disposal, 3D street art, or Trompe-l’œil (French for ‘deceive the eye’), can create an uncanny impression of dimensionality, with the artwork seemingly popping out of the ground.

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