Color models are systems for describing colors so artists, designers, printers, and computers can communicate accurately. A color that looks simple on a screen may be made from red, green, and blue light, while the same color on paper may require cyan, magenta, yellow, and black ink. Understanding color models helps you predict how colors mix, why files change appearance, and how to choose colors for the final medium.
This matters in digital art, photography, graphic design, printing, animation, and web design.
Key Facts
- RGB is additive color: red light + green light + blue light can make white light.
- CMYK is subtractive color: cyan, magenta, and yellow inks absorb parts of white light, and K adds black for depth and detail.
- In 8-bit RGB, each channel ranges from 0 to 255, so RGB(255, 0, 0) is pure red.
- HSB separates color into Hue, Saturation, and Brightness, such as H = 0 degrees, S = 100%, B = 100% for vivid red.
- Approximate RGB to CMY conversion with normalized values: C = 1 - R, M = 1 - G, Y = 1 - B.
- A gamut is the range of colors a device or color model can reproduce, and RGB screen gamuts are often different from CMYK print gamuts.
Vocabulary
- Color model
- A color model is a system that represents colors using numbers, channels, or coordinates.
- RGB
- RGB is an additive color model that uses red, green, and blue light to create colors on screens.
- CMYK
- CMYK is a subtractive color model that uses cyan, magenta, yellow, and black ink to reproduce colors in print.
- HSB
- HSB is a color model that describes color using hue, saturation, and brightness, which often matches how artists choose colors.
- Gamut
- Gamut is the complete range of colors that a device, material, or color space can display or print.
Common Mistakes to Avoid
- Using RGB values for print without conversion is a mistake because many bright screen colors cannot be reproduced by CMYK inks.
- Thinking CMYK works like RGB is a mistake because RGB adds light to get brighter, while CMYK adds ink that absorbs light and usually gets darker.
- Confusing saturation with brightness is a mistake because saturation controls color intensity, while brightness controls how light or dark the color appears.
- Assuming the same file looks identical on every device is a mistake because monitors, printers, papers, inks, and color profiles all have different gamuts and calibration.
Practice Questions
- 1 An RGB color has values RGB(64, 128, 255). Using normalized values from 0 to 1, find the approximate CMY values with C = 1 - R, M = 1 - G, and Y = 1 - B.
- 2 A pixel has RGB(0, 255, 0). What color is it, and what are the approximate normalized CMY values?
- 3 A poster uses a neon blue that looks bright on a monitor but dull after printing. Explain why this can happen using the ideas of RGB, CMYK, and gamut.