SRJC Art Classes of Michael McGinnis

What is the color of a shadow? It depends on many factors such as
lighting, reflectance, material color, and proximity to other objects.

o an artist, shadows are as real as any physical form, although these ghosts are ephemeral, changing before our eyes. There is nothing solid about them, but they define solid objects by giving them volume and weight, and create relationships between objects.

Careful observation and a little knowlege will help you understand what makes shadows look the way they do. You can then put what you see into your drawings.

There are two distinct shadows shown here, and they come in unique shapes and colors. Noticing and understanding them is our goal.

Notice the shadow shapes and colors?
Why is one blue and the other yellow?
Also, why is one sharp and the other diffused?
The reasons can be explained by examining the light sources. There are two distinct sources in the images above. A window is behind, and a spot light shines from the right.

With a large light source, the penumbra gradually
fades because more and more light reaches the paper.

A small light source makes a sharper shadow.

The window allows ambient sky color to flood into the room. Light travels in a straight line until it is either absorbed or reflected, so why is the shadow so diffuse? Because the window is wide and allows a good portion of the sky’s light to come in from many directions. This type of shadow contains two distinct elements: an umbra and a penumbra. An umbra is the fully shaded region of a shadow cast by an opaque object, and the penumbra is the partially shaded region.

The blue shadow is sharper. Notice its size? It is nearly actual size in relation to the object because its light source is small (a miniature spot) and far away. On the other hand, a small light up close would cast a shadow bigger than the object (think film noir). Finally, the blue shadow has a tiny penumbra making it slightly soft.

Now, let's examine the shadows’ colors. In my example, although you cannot see it, the sky is clear and blue, so where the spotlight is shaded, only the sky color is visible on the paper. Alternately, only the spotlight color is visible in the softer shadow. Tungsten light is warm, but not as yellow as the shadow. Yellow reflects off the object’s legs, enhancing the umbra. Note that the penumbra is more neutral.

Note that blue and yellow are complementary.
Their combination makes white light.

With two colored light sources, why does the paper appear white? There is no direct sunlight, so that’s not it. Instead, the white paper is lit from both light sources and blue light + yellowish light = whitish light. White light is being made. But if either one of the light sources were removed (tungsten spotlight or blue sky), we would still see the paper as white. This is the result of color relativity. All colors in our environment shift warmer or cooler as the light sources change, but our eyes adjust so we still perceive the difference between colors as expected. Film and digital cameras do not have this mechanism, so to compensate, film comes in different color temperatures and digital cameras can "white balance" (i.e. daylight, indoor, etc.).

A shadow is sharpest nearest the object.

An almost black line appears below
the foot, at the point of contact.

Here are just two more things to notice about shadows on the paper. First, a shadow is sharpest where it comes in contact with the object. Then it falls off, forming a greater and greater penumbra. How this happens is shown below. Second, under an object, at the point of contact with the paper, a shadow is darkest. An almost black line appears there. This line is important in a drawing for a convincing feeling of weightiness, groundedness, and strength.

Where an object comes in contact with
the surface, the penumbra is smallest.

After examning the effects of shadow on a white surface, let’s look at a white object on a multi-colored surface.

The darkest side of the box in these images contain different colors. Click on each image to see why.

It is clearly demonstrated that objects have an effect on one another with respect to color. The pencil box "takes on" the colors of things around it. If the paint on its surface was flat white instead of an eggshell finish, the color would be more even. This low gloss surface has a slight mirror effect, which produces sharper patterns of reflection, mimicking the scene around it just a bit. The image to the right has the box sitting on a green mat, which has a subtle influence on the directly lit side of the box, while the dark gray mat has a stronger influence in the shadow.

Objects can even affect the directly lit side of the box.
Note the green reflection in the groove shadows.

In the image above, shadows and highlighted surfaces are illuminated by green and orange. It is possible to describe these color reflections as additional light sources. There are two distince kinds of lighting demonstrated here. One is that of a light bulb generating light (which makes it powerful and dominant). The other is reflected light, which is inevitably less bright because its source is also the bulb.

In the end, it can be said that shadows are a combination of these things:

An object’s local color (natural color as seen in ordinary white light)
illuminated by minor light sources
and/or reflections from the environment around it
and that the shadow is not directly lit from the dominant light source.

Relativity is important to understand here. What we think is a brightly illuminated white surface in one environment may match a toned shadow in another, but we may not be able to notice because our eyes automatically adjust to color cast (a predominant color influencing an entire scene, such as warm incandescent lighting or a cool ambient blue sky). Picture this crazy example:

It is noon, and you are in your home, drawing a still-life lighted by three fluorescent bulbs placed around it, with hardly a shadow visible. Then suddenly the roof opens and floods in direct sun light! You will see harsh shadows, whose deepest values are much brighter than in the original still-life.

See I told you it was silly.