Light produces shadow, and the source of that light is important to the painter. The type of shadow is influenced by the light source, which can be high, low, to one side, in front or behind.

The intensity of the light source will affect the tonality of both shading and shadow, and its proximity to the object will affect the intensity of the shadow.

The spectrum of colour can vary, either naturally or artificially, from red to yellows to blues. These colours can be a major influence on the nature of the shadows, shading and the character of the painting.

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Other influences are tone, colour and texture. A light-toned object on a darktoned surface will have much shading but little or no shadow. This phenomenon is often used for portraiture.

A coloured object on a coloured surface will produce coloured shading, often with intriguingly coloured shadows, and will be subject to the tonal influences mentioned above. In the case of texture, imagine the difference in shading between that of a polished ball bearing and a tennis ball, then the kind of shadow that each might produce on surfaces of polished glass and velvet.

There are two forms of shadow: the shape cast by the light and the shading on the object. In each case the object will be revealed as a solid by the issue of darkening tones on the side away from the light source, and will produce a specifically shaped shadow as a result of the same light that reveals it.

Essaouira Fort by Paul Riley
Essaouira Fort, watercolour on Saunders Waterford CP 140lb (300 gsm), 11x20in (28x51cm).

I used the shadow of the building behind me as a framing device for the bottom of the painting. The strong side light was also used to show up the architectural forms. The lighting changed considerably while I was painting, so I fixed on the light and shadow patterns that would best describe the forms


Uses of shading and shadows


To reveal form

The more complex the form, the more important the tonal analysis of the form itself and the surface or surfaces it is adjacent to.

This is noticeable in architectural renderings such as balconies; shadows from trees can indicate undulating surfaces and walls. In fact, the use of strong tonal contrasts will generally aid the depiction of complex building forms.

When working en plein air it is sometime necessary to exaggerate these contrasts in order to make the image work.

For composition

I use shadows to link the various disparate elements, especially in still-life paintings.

In landscape painting, the shadows of trees stretching across the foreground or middle distance will link the leftand right-hand sides of the painting.

Deep diagonal shadows in the foreground can be used to stop and frame the painting, thereby reducing the tendency for the image to ‘dribble’ off the bottom of the picture.

To create atmosphere

Strongdeep shadows can create drama in all kinds of subject matter.

Lighting that produces profound shadows also produces atmospheric buildingscapes, hence these are best observed early in the day or at dusk.

I produce my sketch ideas at these times in order to capture the light, then execute the work later, confident I have the lighting I want.

Girl with Red Scarf by Paul Riley
Girl with Red Scarf, watercolour on Saunders Waterford CP 140lb (300 gsm), 131⁄2x91⁄4in (34x23.5 cm).

In portraiture, particularly with a young face, the shading needs to be subtle. Abrupt changes in tone will considerably age the face. The colours I used were permanent rose, lemon yellow and phthalo blue. To ensure clean clear tones I used stains.


Instructional diagrams for painting shadows

How shadows fall

This basic diagram shows the difference between a shadow and a reflection.

A is the shadow, determined by the height of the light source and its direction.

These two elements can vary, giving longer or shorter shadows continuing at different angles.

The width of the shadow is consistent, due to an even light, such as sunlight, and tangential to the base of the object.

B is the inversion of the object where a is the same length as b.

You cannot see the top of the object in the reflection. All tone (shading) and decoration will be reflected.


Direction of shadows

The basic shadow diagram with tone applied.
 
Note that the tone of the shadow is no darker than the darkest shading on the object, even if the object is white.

2 light sources and shadow in paintings

This illustrates what happens when there are two or more light sources coming from different directions. In this case two light sources have produced two shadows, or umbras, u.
 
The darker area where they cross is a penumbra, p.
 
The intensity of the umbras and penumbras is relative to the light source.

How to paint shadows

When the sun’s rays are almost parallel a phenomenon known as objective parallax occurs.
 
The outsides of the shadow are paler than the central core.
 
Also, the darkest section of the shadow is adjacent to the object. This helps to explain why there is lighting on the dark side of a cylindrical or a spherical object.

 

If there is a concentrated light source the shadow is likely to fan out, as indicated


Shadows can be used to describe forms in adjacent objects.

In the left-hand diagram the shadow of the column is determined by the angle of the light source, A, and the direction of the light source, B.

In the diagram on the right is a window elevation; the shadows have been projected at an angle of 45 per cent.

In order to calculate the extent of the shadows I drew a section with downward projections at the same angle.


Perspective and shadow

When viewing buildings and their reflections obliquely, two-point perspective comes into play.
 
First establish an eye level, then plot the vanishing points 1 and 2.
 
Once the buildings above water level have been drawn, the corner nearest is projected downward so that the line a – b is the same length as b – c. The rest of the perspective can then be worked out.
 
Note that at eye level you can see the top of the quay, whereas in the reflection that is not possible.
 
I have also shown the shadow projection with A being the angle of the light source (sunlight) and B the direction where they meet is the extent of the shadow as indicated by the dotted line.

painting reflections

When viewing reflections on a horizontal plane such as water, certain points should be noted:

  • C shows how angled objects are reflected.
  • B shows that in still water the inversion is the same in height as the object.
  • A shows how perspective extends the reflection in rippled water.
  • D indicates the reflective nature of ripples, where 1 shows the background, 2 the sky and 3 the foreground.
  • In E the face of the ripple facing the boat reflects it. Note how the light rays to the eye get wider as the ripples get nearer. This goes some way to explain why ripples get larger as they get nearer, which equals perspective.

Coloured shadows


This shows the results when two sources of light with different temperatures are used to light an object.

The blue light creates an orange shadow yet the orange light produces a blue one.

The effect is particularly strong if there is no other ambient light

How to paint shadows in colour
This grapefruit shows both shadow and reflection.

Owing to reflected light from the surface of the table, the underside of the fruit is lighter than you might think.

The small dark area under the fruit is a penumbra.

Painting reflected light
 

Flowers with Lemon by Paul Riley
Flowers with Lemon, watercolour on Saunders Waterford CP 140lb (300 gsm), (23.5_34cm)

In this painting the light source is coming from behind (contre jour), which results in the shadows merging with the reflection of the objects. This can produce some magical effects, and the opportunity to inject more colour into the shadows.