Do you draw? If so, ever wondered how light and shadow interact, and that grasping the basics can enhance your drawing skills? Let’s explore the world of light and shadow. I hope the post below will shed more light than shadow on this topic.

Classes of Objects

Objects in nature are categorised into three classes:

Class 1: Sharp & Angular

These are formed by folding a shape to create an edge. (See example below.)

Class 2: Rounded & Less Angular

These are created by revolving a shape. (See example below.)

Class 3:

This category combines elements of Classes 1 and 2. For the purpose of these lessons, we will focus only on Classes 1 and 2, as mastery of these will automatically encompass Class 3.

Differences Between Classes:

1. Sharpness and softness of the form transition.
2. Width of the form transition—it's wider in Class 2 objects.

Form Transition

We use this term to describe the transition of form from one state to another, specifically from light to shadow in our context.

Class 1:

- The edge signifies a transition of form.
- It is straight (though it can vary in shape depending on the object), sharp, aggressive, and clear.

Class 2:

- The form transition is soft.
- Maximum clarity / density is found in the darkest zone of the core shadow.
- The core shadow aligns with the form. (See the cutting plane below that highlights the core shadow.)

When drawing, always be aware of the furthest spot on the shape that you cannot see.

Understanding Light

Let's clarify some key definitions and terminology here.

Highlight: The spot nearest to the light source.

The size of the highlight depends on the object’s radius. Often, it's not clearly visible, but you should be aware of its presence.
Note, that light intensity changes with distance.

Midtone: The area of light between the highlight and the shadow.

Reflected Light: This is light reflected from a surface or object.

Reflected light is always within the shadow zone and is considered part of the shadow. Tonally, it should never be placed in the light zone, except in the case of glass.

Cast Shadow: The shadow an object projects onto a surface.

Cast shadows make objects appear three-dimensional (3D). They reveal the form of objects when cast upon them.

Cast shadow indicates:

1. The shape, form, and slope/pitch of the surface.

2. The position and strength of the light source.

Remember:

- A cast shadow is always darker than the shadow.
- It is most intense and darkest where it meets the object. (See the image below, cube on the right)
- A cast shadow loses intensity and becomes lighter and softer as it extends away from the object.
- Cast shadow edges are sharp near the object casting it and soften as they move away.

Cast shadow is important element in creating 3D illusion on 2D space. So you have to get it right.

Image above:

Left - Incorrect: In this example, the space appears incorrectly turned out.
Right - Correct: The front of the cast shadow is tonally stronger than the rear. The tone strengthens as it approaches the light source and weakens as it moves away.

TONE (VALUE)

Tone: The lightness or darkness of a colour.

Tone changes parallel to the direction of light:
- From foreground to background.
- From top to bottom (if the light source is positioned above the object).

To effectively depict depth in a 2D space, keep in mind the following:
- Elements closer to us are darker, stronger, and denser in tone.
- Elements farther from us are lighter, weaker, and softer in tone.