Understanding Color Theory: Additive and Subtractive Mixing
Color Theory: Additive and Subtractive Mixing
Cone Classification
The cones in our eyes are classified into three types:
- Short-wave cones (blue)
- Medium-wave cones (green)
- Long-wave cones (red)
Additive Color Mixing (Light)
Additive synthesis is the mixing of colored lights. It’s called “additive” because the results are obtained by adding light to light. The sum of the three primary light colors (blue-violet, red-orange, and green) results in white light, the most luminous combination.
Mixing Primary Light Colors
- Green + Red = Yellow
- Red + Blue-Violet = Magenta
- Blue-Violet + Green = Cyan
Mixing the three primary light colors (red, green, and blue-violet) with equal intensity creates achromatic white light (no dominant wavelength).
The absence of light is black.
Complementary Colors of Light
Complementary colors of light, when mixed, produce white light:
- Blue-Violet + Yellow (Green + Red) = White
- Green + Magenta (Blue-Violet + Red) = White
- Red + Cyan (Green + Blue-Violet) = White
Fully Saturated Colors
Fully saturated colors, also known as spectral colors or monochromatic colors, contain no white light. These are the colors displayed in the spectrum of white sunlight (like a rainbow): red, orange, yellow, green, blue, indigo, and violet. Isaac Newton discovered the solar spectrum by passing light through a prism.
Additive Synthesis Methods
- Projecting pure lights onto a white screen in a dark room.
- Newton’s disc: Rotating a disc with the main spectral colors creates the appearance of white.
Subtractive Color Mixing (Pigments)
In darkness, all objects appear black. When light shines on matter, it can be reflected, absorbed, or transmitted, depending on the material’s molecular structure.
Color Transmission
Translucent or transparent materials transmit light without absorbing or reflecting it, appearing colorless. The transmission of light can be affected by the material’s thickness. For example, sunlight can only penetrate water to a certain depth.
Color Reflection
Opaque materials absorb some light rays and reflect others. Their color is determined by the reflected rays.
Subtractive Mixing
Subtractive mixing occurs when pigments are combined. Each pigment absorbs specific wavelengths of light. When mixed, they absorb more light overall, resulting in darker colors. Certain combinations can lead to total absorption, producing black.
Pigment Examples
- Yellow: Absorbs blue-violet and reflects green and red.
- Cyan: Absorbs red and reflects green and blue-violet.
Binary Colors
A binary color, created by mixing two primary colors in equal parts, absorbs two-thirds of white light and reflects one-third.
Subtractive Mixing: Binary Composite Colors
Binary composite colors are created by mixing two primary colors in equal proportions (cyan, magenta, and yellow). Examples include green, blue, purple, red (orange).
The Color Wheel
The color wheel is a visual representation of color relationships, typically arranged in a circle. It displays primary, secondary, and sometimes tertiary colors.
Complementary Colors (Pigments)
Complementary colors, when mixed, tend to cancel each other out, producing gray or black. They are located opposite each other on the color wheel. Examples include:
- Yellow – Blue-Violet
- Magenta – Green
- Cyan – Red
Tertiary Colors
Tertiary colors are created by mixing three primary colors (cyan, magenta, and yellow) in various proportions. They are also known as earth tones. Examples include red-earth (red ochre), olive green, and violet-red.
Color Variables
Hue
Hue is the essential quality that distinguishes one color from another (e.g., yellow, violet, red).
Saturation
Saturation refers to the purity or intensity of a color, ranging from pale to intense.
Brightness
Brightness is the visual sensation of lightness or darkness.
Tones and Brightness
Tones can be ordered by brightness (from 10 – highest to 0 – lowest):
- White (10)
- Yellow (9)
- Red (8)
- Orange (7)
- Magenta (6)
- Green (5)
- Cyan (4)
- Blue-Violet (3)
- Black (0)
Adjusting Saturation and Brightness
- Saturation: Decreased by adding white, gray, or the complementary color.
- Brightness: Decreased by adding black.