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
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,M=1−G,Y=1−B
(If RGB values are normalized to 0–1)
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:
-
H (Hue): The color type, measured as an angle (0°–360°) on a color wheel.
- Red = 0°, Green = 120°, Blue = 240°
-
L (Lightness): Measures brightness from black (0%) to white (100%).
-
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.
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).