Light & Shadows

"Shadow is a colour as light is, but less brilliant; light and shadow are only the relation of two tones."

                  – Paul Cezanne

Where there is light, there's always shadow, multi tones. Without them any picture would seen life less. It's the shades and reflections that give form to any object and breath to a picture... Creates an illusion of three dimension.

Theoretically, a shadow is light blocked by an object. The object can block all or part of the light and based on the closeness to the light source the shadows change size. Shadows can be formed by one light source or more light sources. The Sun, lamps, flashlights, and fires are all sources of light. Not to complicate and as a beginner, I am concentrating on single light source. 

The Will Kemp Art School 's A Beginners Guide to Light & Shadow  gives a good idea on the theory of shadows. 

Almost all objects in the nature can be reduced to basic shapes... All are a variation of the basic shapes such as spheres, cubes, Cylinder and cone. Thus, if we understand the response to light on these objects or shapes, we can very much adapt them for any object in the nature.

Light always travels in a straight line and the shadows they produce are always in a direct response to the object the light hits, the angle at which the light is coming and the intensity of the light source.

So, if a bright, high sunshine hits a tree directly from above, it makes a short shadow shape. When the sun is very low, it will make a longer shadow shape, almost the shape of the tree.

Now, if a single light hits a cube, it will make a square shape shadow. 

Similarly, if a single light source hits a sphere, an ellipse shape shadow is produced. 

This is called ‘light logic’ and the shadow produced is called a Cast Shadow.

Cast Shadow

The characteristics of the cast shadow are dependent on the intensity of the light source. A hard light will produce a cast shadow with a sharp edge, a soft light will produce a cast shadow with a more blurry edge.

The longer the cast shadow is from the object, the softer the edge of the shadow becomes as shown in the picture above. Source is natural light entering the room. The shadow is darkest near the base of the object and becomes lighter and lighter as it moves further away.

Again, the shape of the shadow depends on the surface it falls as well. On a flat surface, everything will be as expected. Let's stick to flat surface!

Now, coming to the light falling on the object and the tones that it creates.

The light source is on the leftmost corner. 

The whole object can be divided into three regions, namely, light side, shadow side and the cast shadow. The shadow line is the transition between the light region and the shadow region.

1. Light Side

The light side includes the highlight (1) and the half tones (2). 

The Highlight is the lightest part where the light directly hits the object. 

Half tones can be same tones or lighter and darker on either side. This region directly receives light from the light source and are always lighter in value than the lightest value on the shadow region.

The Halftones blend into the shadow region and make the highlight appear white. 

Highlights make the drawing come to life. 

2. Shadow Side

The shadow side includes the Form Shadow (4), the Form Shadow Core (3) and Reflected light (5).

The Form Shadow Core, or terminator, is the darkest dark part of the shadow region where no light hits the object, and it appears as a line or plane parallel to the light source. 

The rest of the Form Shadow is made up of dark tones that blend away from the shadow core into the reflected light, if there is any.

Reflected light, or bounced light, is the light reflected onto the object, from the surface it sits on or ambient light around the object. For example, the shadow side of a sphere is slightly illuminated by light bouncing off the floor and onto this side of the object. The color of the object is often most true in this area. White or shiny surfaces reflect the most light, dark or black surfaces reflect the least amount of light.

Reflected light rounds the form. It is never darker than a cast shadow or lighter than the shadow area that appears on the periphery of the area in light region.

3. Cast Shadow

The vocabulary used to describe cast shadows (6) in art come from shadow descriptions in astronomy. The umbra, penumbra and antumbra are the three distinct names given to the description of shadows cast by heavenly bodies. The umbra (7) is the darkest part of a shadow considered the absence of light. The penumbra (8) is a lighter outer shadow where the object is only partially obscuring the light. The antumbra (9) is more obscure. When it is visible it seems to extend out from the penumbra in a lighter and less distinct way.

Let's try with watercolor. Will come with the results soon...

Till then, take care and Happy painting. 

🙏

06.06.2021