Page 20 - DCAP504_Computer Graphics

Unit 2: Colors in Computer Graphics

The computer monitor’s screen is black, that is, it emits no light. The color display is
created, when the three primary colors RGB are generated. Intermediate colors are
produced, when there is a variation of the intensities of the red, green, and blue colors.

A unit cube is used to represent the color space of RGB colors. This unit cube is placed at origin in its
standard position. The figure 2.2 depicts the color co-ordinate system with the three primary colors of
RGB model, that is, RGB.

Figure 2.2: Color Co-ordinate System with RGB Colors

Source: Schaum's outline of theory and problems of computer graphics
Each of the RGB (primary) colors can take up the intensity value ranging from 0 being the lowest to 1
being the highest. When these primary colors are mixed at different intensity levels, they produce a
variety of colors including cyan, magenta, yellow, and white. The collection of all the colors available by
such a linear combination of red, green, and blue forms the cube-shaped RGB color space as shown in
figure 2.2. The corner of the RGB color cube that is at the origin of the co-ordinate system corresponds
to black. The corner of the cube that is diagonally or obliquely opposite to the origin represents white.
The oblique line connecting white and black corresponds to all the gray colors between white and black
and it is called as the gray axis.
With the help of this RGB color model, a random color within the cubic color space can be specified by
its color co-ordinates, that is red, green, and blue.

(0,0,0) is for black, (1,1,1) is for white, (1,1,0) for yellow.

The color specification using the RGB color model is an additive process. First, black color is considered
and the suitable primary component is added on to yield a preferred color.

Research and find the resultant color, when the color intensity of RGB is (1, 0.7, 0.7).

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