- Slides: 15
Chapter 12 COLOR THEORY
Overview: • Color theory • Color spaces • Color model • Types of Color model • Additive and Subtractive Color model • Mechanism of human eye • Cones and Rods • What is CIE
What is Color theory A color model is an orderly system for creating a whole range of colors from a small set of primary colors. Color theory is the study of color and its role in art and design
Color Spaces • A range of colors can be created by the primary colors of pigment and these colors then define a specific color space. • Color space, is also known as the color model. • It is an abstract mathematical model which simply describes the range of colors typically as 3 or 4 values or color components (e. g. RGB).
Color model • A color model is an orderly system for creating a whole range of colors from a small set of primary colors.
Two Most Common Color Models There are several established color models used in computer graphics, but the two most common are the RGB model (Red-Green-Blue) for computer display and the CMYK model (Cyan. Magenta-Yellow-black) for printing.
Types of Color model 1) RGB Color Model: • • • Additive color model. For computer displays. Uses light to display color. Colors result from transmitted light. Red + Green + Blue = White
2) CMYK Color Model: • • Subtractive color model. For printed material. Uses ink to display color. Colors result from reflected light. • Cyan + Magenta + Yellow = Black.
• The RGB color model is used in hardware applications like PC monitors, cameras and scanners, and also has been used in conventional photography. • The CMY color model is used in color printers, and is also used to describe the printing process itself.
Additive color and Subtractive color models • Additive color is color created by mixing light of two or more different colors. • Red, green, and blue are the additive primary colors normally used in additive color system. • Since additive color models display color as a result of light being transmitted, the total absence of light would be perceived as black.
• A subtractive color model explains the mixing of a limited set of dyes, inks, paint pigments or natural colors to create a wider range of colors. • Subtractive color models display color as a result of light being absorbed (subtracted) by the printing inks.
Mechanism of eye in understanding color • When light is reflected off of an object, the light enters the eye through the pupil and is flipped upside down by a clear lens that is just behind the iris. • The image is then projected through the body of the eye and onto the retina which the main stage for where color vision is generated.
Cones and Rods • Cones are responsible for daytime vision, color vision and the finer details of the things we look at. Cones are activated by a certain amount of light, which is why we don't see colors in the dark. • Rods are responsible for night vision and handle vision in low light. They allow sight of general shapes and forms.
What is CIE color model • The CIE color model is a color space model created by the International Commission on Illumination. • It is also known as the CIE XYZ color space or the CIE 1931 XYZ color space. • The CIE specification is supposed to be able represent every single color the human eye can perceive.