Color models

VizPaint2D offers several different ways to choose colors.

• You can pick any color from the canvas. This allows you to match the shades in your existing pictures.
• You can display blocks or a continuous spectrum of colors, then choose the exact shade you want from those displayed.
• You can specify color using three color models: HSV, RGB, and CMY.

The following paragraphs describe how you use the HSV, RGB, and CMY color models to specify colors in VizPaint2D.

HSV model

The HSV model separates color into three components:

• Hue (H) corresponds to the pure colors of the rainbow, such as yellow, blue, and green
• Saturation (S) is the amount of white mixed with the hue to set the intensity of the color
• Value (V) is the amount of black mixed with the hue to make it darker

In VizPaint2D, you blend color by adjusting sliders or entering a value that corresponds to a slider's position. The range of values for HSV is as follows:

• H-0 to 360 degrees, where degrees represent the colors of the spectrum: red is 0, yellow is 60, green is 120, cyan is 180, blue is 240, magenta is 300, violet is 315
• S-0 to 1, where 0 is white and 1 creates a completely saturated color which has no white
• V-0 to 1, where 0 creates black and 1 is pure color

The HSV color model is also the basis for four VizPaint2D composition modes: hue, saturation, value, and watercolor. (See page 374 for a description of these composition modes.)

RGB model

The RGB model uses varying amounts of three primaries-red, green, and blue-to create color. The RGB model is known as additive color because adding 100% of three primaries produces white, combining 0% of the three primaries creates black, and adding equal amounts of all primaries produces gray.

CMY model

The CMY model uses varying amounts of cyan, magenta, and yellow as its primaries to create color. The CMY model is known as subtractive color because combining 100% of its primaries produces black and 0% of all three results in white.

Combining additive and subtractive color

If you have never edited color before, it helps to know the combinations for primary and secondary colors. Then you can start with the primary or secondary closest to the color you want to create and change one slider at a time to create an exact shade.

Table 6 shows the RGB values for primary and secondary colors.

Primary and secondary RGB color values

Color
Red	1	0	0
Green	0	1	0
Blue	0	0	1
Cyan	0	1	1
Magenta	1	0	1
Yellow	1	1	0
White	1	1	1
Black	0	0	0

Table 7 shows the CMY values for primary and secondary colors.

Primary and secondary CMY color values

Color
Red	0	1	1
Green	1	0	1
Blue	1	1	0
Cyan	1	0	0
Magenta	0	1	0
Yellow	0	0	1
White	0	0	0
Black	1	1	1