Published on March 31, 2014
Color BY HASHMI SAFWAN
What is color ? Color is a sensation produced by the human eye and nervous system. It is useful to represent a color by a set of exactly three numbers.
Color is Human Sensation Cone and rod receptors in the retina Rod receptor is mostly for luminance perception 3 different types of cone receptors in the fovea of retina, responsible for color representation. Each type is sensitive to different wavelengths
Color model A color model is an orderly system for creating a whole range of colors from a small set of primary colors.
Types of Color model Subtractive Color Additive Color Additive color models use light to display color subtractive models use printing inks.
The Two Most Common Color Models RGB model For computer CMYK model For printing YCbCr model
RGB Color Model: Additive color model. For computer displays. Uses light to display color. Colors result from transmitted light. Red + Green + Blue = White.
The RGB Color Model If R,G, and B are represented with 8 bits (24-bit RGB image), the total number of colors is (28 )3=16,777,216
CMYK Color Model Subtractive color model. For printed material. Uses ink to display color. Colors result from reflected light. Cyan + Magenta + Yellow = Black Used internally in color printers Complementary to RGB: C=1-R M=1-G Y=1-B
Color Models the color model RGB is used in hardware applications like PC monitors, cameras and scanners, the CMY color model is used in color printers, Each color can be a point in the RGB color model cube. Red, green and blue are known as the primary colors. These colors can be added to produce secondary colors which are: magenta = red + blue cyan = green +blue yellow = red + green Other possible combinations: white = blue (primary) + yellow (secondary) white = green (primary) + magenta (secondary) white = red (primary) + cyan (secondary)
Additive vs. Subtractive Color Models Since additive color models display color as a result of light being transmitted (added) the total absence of light would be perceived as black. Subtractive color models display color as a result of light being absorbed (subtracted) by the printing inks. As more ink is added, less and less light is reflected. Where there is a total absence of ink the resulting light being reflected (from a white surface) would be perceived as white.
HSL and HSB Hue Hue is what most people think of when we say "color". Saturation Saturation is the "purity" of the color. It refers to the amount of gray paint mixed with the hue. Lightness Value refers to the intensity of light present.
HSL and HSB
Dithering Dithering is often used for displaying monochrome images creating the illusion of new colors and shades by varying the pattern of dots. Sometime call halftoning.
YCbCr YCbCr Color Space is used in MPEG video compression standards • Y is luminance • Cb is blue chromaticity • Cr is red chromaticity Y = 0.257*R + 0.504*G 0.098*B 16 Cr = 0.439*R 0.368*G 0.071*B 128 Cb = 0.148*R 0.291*G 0.439*B 128 YIQ color space (Matlab conversion function: rgb2ntsc):
A color model is an abstract mathematical model describing the way colors can be represented as tuples of ... we call these models color mechanism models.
Realtime 3D Computer Graphics / V irtual Reality Ð WS 2005/2006 Ð Marc Erich Latoschik Color Models ¥ Used to describe color as accurately as possible.
Colors can be described in many different ways, each method based on a color model. For example, the RGB color model is based on creating colors by adding ...
Color Models . The search for a comprehension of exactly what color is and how it functions has been going on for hundreds of years. Numerous models and ...
The notation Lab in graphics software almost always represents the CIELAB color space. In this text, Lab will be also used in reference to CIELAB.
HSV • This color model is based on polar coordinates, not Cartesian coordinates. • HSV is a non-linearly transformed (skewed) version of RGB cube
Color appearance. Color originates in the mind of the observer; “objectively”, there is only the spectral power distribution of the light that meets ...
Color Models. Color models are used to classify colors and to qualify them according to such attributes as hue, saturation, chroma, lightness, or brightness.
A color model is a system for creating a full range of colours from a small set of primary colors. There are two types of colour models: additive and ...
RGB color space or RGB color system, constructs all the colors from the combination of the Red, Green and Blue colors. The red, green and blue use 8 bits ...