Shadows and reflections – what your art class forgot to teach.

January 29, 2013 in ideas, slideshow

Light is what makes everything visible. With the information we read from the shadows we are able to determine the shape of objects without touching them. Drawing classes often teach us through practical experience – copying the shadows and highlights of simple objects over and over again. However, the great masters of painting researched lighting further than that. It is much easier to put a still life on paper if one understands the way lighting interacts with the objects.

Shadows

A shadow is an area blocked from the light, usually behind an object. There is rarely such a thing as a complete shadow. In a natural environment, light bounces around and reflects from surfaces. Therefore even the shadow areas receive a certain amount of light.

The surfaces directly facing the light source are the brightest, transforming smoothly into a shadow over curves or sharply over angles. In case of texture, the coarseness of the surface will be visible because of the shadows from the reliefs. Even a highly textured surface will appear flat, if lit perpendicularly to the texture.

Depending on the light source, the shadows can be sharp or diffuse. A small or distant light source such as the Sun or a spotlight cause crisp, sharp shadows. A large light source nearby such as a window or a shaded lamp cause more diffuse shadowing. On a cloudy day when the whole sky functions as a light source, the shadows are extremely diffuse and clearly visible only in secluded crooks that are hard for the light to access.

There is a false theory about shadows being the opposite colour of the light source – this is not true. If there is no light, the shadows are black. However, our eyes do like to see an optical illusion of toned shadows in the opposite colour of the light. This is a similar phenomena to the afterimage we see on our retina after staring at a coloured object for long enough – close your eyes and you will see an image with inverted colours before your eyes. When looking at a strongly coloured light, the shadows will seem the opposite colour as our eyes grow tired of the main hue. Painters often use coloured shadows to underline this illusion that we receive through our eyes.

The actual reason for coloured shadows is the reflected light from the surrounding surfaces. As light bounces off an object, the colours not present in that object will absorb into the surface. For example a red wall will absorb all other colours, and reflect red light only. A good example of this are the distinct blue shadows on a sunny day outdoors – the colour comes from the light bounced from the blue sky. Paying attention to the colour of nearby surfaces and thinking about the travel path of light will help you determine the colour of shadow areas and make the picture more realistic.


The picture has been cut diagonally – the lower part of the photo is taken without the red toy – notice how it reflects red colour on the back of the white box.

Reflections

Reflections give us an understanding of the space around our subject frame. They help to determine the direction of light and can reveal the number and positioning of the light sources.

Reflections are more visible under a steep angle. We will see bright, sharp reflections on the curved edges of a round vase, never facing us directly. When looking over a calm pond, the water is more reflective further away, never directly at our feet.

There are two kinds of reflections – diffuse and direct. Most materials usually display a mix of these at the same time.

Direct reflections are specular highlights, direct images of the light sources in the space. They brightest ones have the shape and size of the light source. The smoother the surface, the clearer is the direct reflection it creates. The ultimate example is a mirror, able to reflect not only the light sources, but also all other objects. Another good example of direct reflection is the highlights in the eyes of portraits. On rough and textured surfaces, the direct reflection becomes blurred, but it should be remembered that it still represents the size and shape of the light sources and objects around them.

Diffuse reflection is present on all objects: all surfaces reflect light to some extent. This is what makes them visible for us. The light needs to reach our eye directly from the surface of the object. When light hits a surface and reflects back, the direction of reflection is more or less random, diffusing the light and breaking up the image. This is why the object is seen from all directions. It also appears to have a solid surface: all light received from the environment is mixed into an even blend.

Have a look at different materials of these objects and how they reflect the light. Notice how the table is very reflective as well. The only light source here is a window on the right. 

Refraction

When light passes through transparent materials,  it usually bends. This is an important issue with glass and water (and especially glasses full of water). The bending direction depends on the lighting angle – it always adjusts to be more perpendicular to the surface.

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