Value: Lesson 4 – Light and Shadow: Principles and Perception

1. Understanding Value: What is it?

Value refers to  the lightness or darkness of tones, essential for creating depth & form. It defines how light interacts with objects, shaping their appearance through highlights, mid-tones, and shadows.

For example, in a black and white photograph, the infinite variations of gray convey planes, textures, and depth, demonstrating the power of value to suggest form without color.

Value Scale:

• White (High Key): Lighter values
• Gray (Midtones): Intermediate values that transition between light and shadow.
• Black (Low Key): Darker values

2. Principles of Light and Shadow

Light Source and Its Impact:

The position of the light source determines how light and shadows are distributed on an object.

In this example, observe the highlight where light directly hits the lemon. If you draw an imaginary line connecting the highlight and the cast shadow and extend it outward, it points to the light source. This illustrates a key principle: The cast shadow always falls on the side opposite the light source.

Under artificial lighting with multiple light sources, multiple shadows are cast. Including too many shadows in work can create confusion. In such cases, it’s best to select the most dominant shadow to maintain clarity.

Types of Shadows:

1. Highlight: The brightest spot where light hits directly.
2. Light Area: The area receiving moderate light, transitioning from the highlight to the shadowed side.
3. Reflected Light: Light bouncing off surrounding surfaces, softly illuminating the shadowed area.
4. Cast Shadow: The shadow projected by the object onto another surface with edges
5. Core Shadow: Darkest part of the form

3. Perception of Value: How We See Light and Shadow

Optical Illusions and Value:

Value is not just about light and dark; it’s about perception. Our eyes perceive value relative to the surrounding tones, which can create optical illusions.

This demonstrates the principle of simultaneous contrast, where identical values appear different depending on their background. The mid-gray circle looks darker against a light background and lighter against a dark background. This phenomenon is a powerful tool for artists to manipulate and control value adjustments, creating depth, emphasis, and emotional impact.

Reflected Light and Optical Illusions:

From my teaching experience, reflected light is one of the most challenging concepts for beginners. Students often make the reflected light too bright because of an optical illusion: surrounded by dark shadows, the reflected light appears lighter than its actual value. This is a perceptual trap!

How is Reflected Light Created?

Keep in mind that reflected light is generally created by white, light-valued, or reflective surfaces.

Dark-valued or soft materials absorb light and do not produce reflected light.

• Value is fundamental in creating depth, form, and realism by controlling light and shadow.
• The light source determines the placement and intensity of shadows.
• Optical illusions influence our perception of value, making it essential for artists to understand and manipulate.
• Reflected light is often misjudged due to optical illusion. Because reflected light is surrounded by the darkest values – core shadow & cast shadow. it’s crucial to constantly compare with the neighboring values. You can also use the value scale to compare.

Please watch the video demonstration of Light and Shadow.