1. RGB Color Model (Additive Model)

Definition: The RGB color model represents color as a combination of Red, Green, and Blue light. It is called additive because colors are created by adding light of these three primary colors.

Components:

• R (Red): 0–255
• G (Green): 0–255
• B (Blue): 0–255

How it Works:

• When all three components are at maximum (255, 255, 255) → White
• When all are zero (0, 0, 0) → Black
• Combinations produce all other colors.

Applications:

• Computer monitors, TVs, digital cameras, displays.

Example:

• (255, 0, 0) → Red
• (0, 255, 0) → Green
• (0, 0, 255) → Blue
• (255, 255, 0) → Yellow

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2. CMY Color Model (Subtractive Model)

Definition: The CMY color model represents color using Cyan, Magenta, and Yellow pigments. It is subtractive, meaning it works by absorbing (subtracting) light.

Components:

• C (Cyan)
• M (Magenta)
• Y (Yellow)

How it Works:

• Cyan absorbs Red
• Magenta absorbs Green
• Yellow absorbs Blue
• Mixing all three ideally gives black. (In practice, black ink K is added → CMYK)

Applications:

• Printing, physical media, color separation in publishing

Example:

• C + M → Blue
• C + Y → Green
• M + Y → Red

Relation to RGB:

• CMY is the complement of RGB: $$C = 1 - R, \quad M = 1 - G, \quad Y = 1 - B$$ (If RGB values are normalized to 0–1)

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3. HLS / HSL Color Model (Hue, Lightness, Saturation)

Definition: The HLS (also called HSL) model represents color in terms of human perception, focusing on hue, lightness, and saturation rather than primary color components.

Components:

1. H (Hue): The color type, measured as an angle (0°–360°) on a color wheel.

   • Red = 0°, Green = 120°, Blue = 240°

2. L (Lightness): Measures brightness from black (0%) to white (100%).

3. S (Saturation): Measures color purity (0% = gray, 100% = fully vivid).

Advantages:

• More intuitive for humans to adjust brightness, color intensity, or choose colors.
• Useful in graphics software and UI design for color pickers and palette adjustments.

Applications:

• Image editing, visualization, interactive design, and digital painting.

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4. Comparison of RGB, CMY, and HLS

Model	Type	Components	Range	Use
RGB	Additive	Red, Green, Blue	0–255	Displays, monitors
CMY	Subtractive	Cyan, Magenta, Yellow	0–1 (or %)	Printing, physical media
HLS	Perceptual	Hue, Lightness, Saturation	Hue: 0–360°, L&S: 0–1 or 0–100%	Graphics software, color selection

Key Points:

• RGB → CMY: Complementary relationship (used in conversions).
• HLS: Focuses on human-friendly representation rather than device-based.
• Choosing the right color model depends on application context (screen vs print vs perceptual editing).